Welcome back to Sports Mole for live coverage of the 113th US Open. It doesn't feel like we have been away all that long, and it's going to be another long one today.

We're just catching up with the rest of the action from this morning's continued first round. Donald has dropped a shot at the 16th hole, meaning that he falls back to three-under-par with Phil Mickelson. Here's the what the top of the leaderboard looks like...

LEADERBOARD: (-3): Mickelson (F), Donald (18); (-2) Simpson (8), Goggin (5), Presnell (5); (-1) Colsaerts (F), Westwood (18), Hedblom (12), Goya (12)

Tiger Woods left a putt overnight on the 11th green, but managed to tidy up to save par. However, he gave away a shot on the very next hole, again with a missed putt from inside five feet, to drop to two-over with two holes of his first round left to play.

Rory McIlroy has also dropped a shot today, which sees him at one-over-par. Lee Westwood has just posted a bogey at the 17th to slip back to level par.

The morning has not been kind to Adam Scott. He dropped shots early on today at 12 and 14. A double added to his woes, meaning that he has crumbled from three-under to one-over-par.

MISS! Oh dear, Donald pushes a par putt wide on the 18th green, which means he enters the clubhouse on two-under-par. Still, he should be happy with his first round.

Lee Westwood posts a level-par round of 70. Again, there's nothing wrong with the score.

BOGEY, BOGEY! Webb Simpson and Ernie Els both drop shots at 15, which puts them level par for their first round.

MOVING UP Kyle Stanley birdied the short par-three 13th and made par of the 14th to get to two-under-par. He still have four holes of his first round to navigate. Can he stay second on his own, or can he challenge the lead?

McIlroy and Woods both find themselves in precarious predicaments in the rough, although Tiger's is by far the worse shot. McIlroy doesn't catch his at all cleanly, and will have a chip from the fringe for par. Tiger does about as good as he could, hitting from above his feet on an up-slope.

BOGEY, BOGEY, BOGEY! Scott (+2), McIlroy (+2) and Woods (+3) all end up marking a bogey on their card for the 17th hole.

The leaderboard has been going backwards this morning. The wind has picked up a bit at Merion, which is making the course play extra tough. We all saw how much the soft conditions aided low scoring yesterday (it didn't), so it seems that the players are in for a real test today.

BIRDIE! Australia's Matthew Goggin knocks a deceptively testing short putt at the 12th to join Luke Donald on two-under-par.

"It's cold and damp, and there's a bit of a breeze about. 70 is a good score," Lee Westwood tells Sky Sports News.

BIRDIE! Kyle Stanley dropped a shot at the 15th, but he's more than made up for it with a tremendous putt from off the green at 16 to get back to two-under-par. That one tracked right into the hole.

Tiger Woods signs for a three-over round of 73.

McIlroy found the front bunker at 18 and his pitch out left him with over 10 foot to save par, but he wasn't able to do so. The Northern Irishman sent the putt wide of the cup, which means he also settles for a three-over round of 73.

Webb Simpson pulls a putt wide at the 17th hole, meaning that he drops back to one-over-par. He played beautifully for the few holes he traversed yesterday, but things have been going backwards for him, and many others, this morning.

Adam Scott two-putts the 18th to finish his first round on two-over-par, one shot better than his playing partners McIlroy and Woods.

Gonzalo Fernandez-Castano (+1) posts 71 for his opening round. That's not a bad score at all.

Branden Grace is currently going well on one-under-par. He's on the sixth hole (his 14th), while Nicolas Colsaerts, who is also one-under, is preparing for his second round. Speaking of preparing for the second round, the ground staff are now 're-setting' the course, which means cutting new pin positions on the quickening greens.

BIRDIE, BIRDIE! Russell Knox and KJ Choi both sink birdie putts on the 15th and 16th respectively, which hauls those two to even par.

At the moment, only five people are under par. Mickelson (-3) leads the way, followed by Luke Donald (-2). A bogey at the fourth hole for Matthew Goggin sees him drop back to one-under-par, alongside Nicolas Colsaerts and Branden Grace. However, the Australian still has five holes of his first round left to play.

Webb Simpson and Ernie Els both post one-over rounds of 71. The leaderboard is very bunched, with 49 players within five shots off the leader Phil Mickelson. But with conditions looking tougher this morning, who knows what the lead will be by the end of today?

LEADERBOARD: (-3) Mickelson; (-2) Donald; (-1) Colsaerts, Goggin, Grace; EVEN Clark, Schwartzel, Kelly, Day, Fowler, Westwood, Hedblom, Senden, Choi, Bettencourt, Knox; (+1) D. Johnson, Watson, Stricker, Rose, Coetzee, Hoffman, Huh, Poulter, Stallings, Goya, Phelan, Fernandez-Castano, M. Thompson, Els, Simpson, Pettersson, Stanley, Streelman, Presnell, Kim; (+2) Mahan, Cink, Stefani, N. Thompson, Weir, Pan, Scott, Van Pelt, Hwang, Loar, Matsuyama, Herman, Alker

BIRDIE, BIRDIE! Goggin sinks a 30-footer for birdie at the sixth hole to rejoin Donald on two-under-par with four holes of his first round left to play. Russell Knox gets to one-under with a birdie at the 16th.

It's just about 10 minutes until Luke Donald (-2), Lee Westwood (E) and Martin Kaymer (+6) tee off their second rounds at Merion. Quick turnaround, not a minute to be wasted. We won't be getting the second round done today, though.

Rory McIlroy reflects on his first round at Merion: "I played OK, although I struggled this morning as the conditions were trickier today. The trouble is this course is just so penal compared to other courses, there are a few tee shots you have to be careful with and be more conservative with than usual."

Tiger Woods: "It's unbelievable how much faster [the greens] were this morning. It should slow up a little bit this afternoon. There is moisture in the greens and uphill putts are really slow but the downhill putts are really quick."

So the second round is underway and it's started with a par at the first for Peter Hedblom (E). Goggin (-2) and Knox (-1) are still completing their first rounds.

Branden Grace, who is also finishing his opening round, is even-par through 15 holes.

Donald and Westwood, starting at the par-four 11th, both find the green in two, but will have difficult putts for birdie.

BIRDIE! Hedblom (-1) gets himself back under par with a birdie at the second. His approach into the green was spectacular and a birdie is exactly what it deserved.

Westwood runs his birdie putt past the hole and leaves himself with a tricky one coming back. Donald's putt was good for pace but the line was all wrong.

HOLED OUT! American amateur Gavin Hall finds the cup for an EAGLE with his second shot on the par-four seventh hole. The ball landed above the pin and bit back towards the cup before disappearing. That gets him to three-over-par. Nicely done.

Scotland's Russell Knox, playing in his first US Open, signs for a one-under round of 69, joining Nicolas Colsaerts in a tie for fourth.

BOGEY! Westwood (+1) can't find the bottom of the cup with his second putt for par at 11. That's a bad start to the second round for the man from Worksop.

It has been an intriguing morning at Merion. The wind has picked up, but by all accounts, it will be far worse this afternoon. You just cannot predict what the leading score will be by the end of today. There's a very good chance that nobody will be under par. Typical US Open, I guess...

Branden Grace posts an even-par 70 for his opening round. Anything around two, three-over-par is a decent score. So not bad, not bad at all...

The marquee group are about to tee off at the 11th.

All three players step up to the ball with irons in hand and put their ball in play on the fairway. No drama.

Matthew Goggin (-2) keeps his round going with a par at the eighth. He is through 16 holes now.

Westwood comes up well short of the pin with his approach to the 12th green. The ball lands on the front of the putting surface and spins back a little, leaving him on the fringe. He doesn't look too happy with that, he has a bit of work to do there...

TIED FOR THE LEAD! Once again, Donald gets himself to three-under-par with a brilliant 20-foot putt on the 12th green. His blade has been very hot from that sort of distance so far this week.

Westwood's putt from the edge of the green was weighted nicely, but it never looked on target. He has a couple of feet left for his par, which he trickles in. Meanwhile, Woods, McIlroy and Scott all find the green in two at the 11th.

Scott goes close with his long-range putt for birdie at 11, swinging it from left to right. Woods also comes within inches of picking up a shot, but his effort ends up rolling a couple of feet past the hole. He tidies up for par, though.

BIRDIE, BIRDIE! McIlroy's second into the green at 11 was brilliant, and left him with a tiddler. It was far from a foregone conclusion for the Northern Irishman, who hasn't been great with the short club of late, but he rolled it and moves to two-over-par. On the 13th, Donald went long with his tee shot, but a glorious chip from the rough tracked right into the hole and he now leads on four-under-par! A bit of magic there from the short-game master!

Westwood (+1) goes agonisingly close to getting a shot back at the 13th. His birdie putt had a massive right-to-left swing and he judged it near perfectly, but not quite...

Woods sprays his tee shot at the 12th way right and he's in the trees. McIlroy and Scott are plonked centre of the fairway.

Matthew Goggin has posted a two-under 68 for his opening round. Great effort.

EAGLE! D.A Points (+5) cards an eagle two at the par-four first hole!

Scott's shot isn't a good one, but Tiger's is. He got a bit lucky by finding his ball in the rough and chopped it out to around 15 foot of the cup. McIlroy has a similar distance for his birdie.

Westwood's tee shot at 14 puts him in a spot of trouble.

Woods starts his second round with two consecutive pars. His putt at the 12th wobbled left and right but it kept true in the end, meaning that he'll stay on three-over-par.

BIRDIE! Rory McIlroy (+1) is making a move early in the second round with another birdie at 12! That putt from around 15 feet should give him real confidence around these greens. His start to the second round is a far cry from how he finished his first this morning.

BOGEY! And it's three different outcomes for the three players in the marquee group, as Scott's par putt wipes its feet before deciding not to drop. The Australian is now three-over-par having started the day on three-over just past the half-way point of his first round.

Tiger's tee shot at the short par-three 13th lands above the flag and spins back towards the hole. That leaves him with a makeable putt for birdie. Scott's approach pitches in a similar pace, but has far more bite on it, ending up around 10 feet from the hole.

McIlroy's putt at the 13th doesn't find the cup but he taps in for par.

BIRDIE, BIRDIE! Scott (+2) gets the shot that he dropped at the 12th back with a perfectly-judged putt at the 13th. Woods's putt is trickier than it looks, but he holes it to get to two-over.

DOUBLE BOGEY! Oof, that's not good from Westwood, who drops to three-over-par with a double at the 14th. It was his tee shot that got him in trouble, but a spot of damage limitation sees him drop just the two shots.

John Senden has started his second round with four-straight pars and he is tied for seventh, even-par for the championship.

Woods, Scott and McIlroy put their balls in play on the par-four 14th.

Westwood, looking to recover from his double on the previous hole, finds the centre green at 15, but Donald pulls his approach into the bunker.

BIRDIE! Senden has just birdied the fifth hole and he joins Colsaerts, Knox and Choi on one-under-par.

Donald's stance from the bunker was awkward, to say the least. It was more akin to a baseball shot, but he gets it out the trap and onto the putting surface. If he can make par from there it'll feel like a shot gained. His approach with the wedge was a tad wayward.

McIlroy can't find the green with his approach to the 14th. Scott's approach is far better and he'll have a chance of birdie from around 10 feet.

BOGEY, BOGEY! Donald drops back into a tie with Mickelson on three-under once again. However, it's Westwood who is truly unravelling here, as another dropped shot puts him at four-over-par. He needs to get something going quickly.

Woods is also off the green at 14, but he's putting from the fringe. His effort didn't have nearly enough pace on it, and only finishes just inside Scott's marker. McIlroy has pitched to a similar distance and will have that for par.

The greens really are running noticeably faster now. Scott taps his putt from 10 foot, and he does not miss the cup by much. That'll be par, which keeps him at two-over.

BOGEY! Woods (+3) drops shots at the 14th.

BIRDIE! John Senden continues his great start to the second round by picking up another shot and moving onto two-under-par.

BOGEY! A dropped shot at the fourth sees KJ Choi slip to even par. He scrambled well and nearly made his long-distance par putt, but it wasn't to be.

Scott gets into trouble off the 15th tee, but Tiger hits the middle of the fairway. McIlroy will also find his ball in the short grass.

LEADERBOARD: (-3) Mickelson, Donald; (-2) Senden, Goggin; (-1) Colsaerts, Knox; EVEN Choi, Clark, Schwartzel, Kelly, Day, Fowler; (+1) M. Thompson, McIlroy, Fernandez-Castano, Els, Grace, Matsuyama, D. Johnson, Watson, Stricker, Rose, Coetzee, Hoffman, Huh, Poulter, Stallings, Phelan

Donald hits the green with his tee shots at the par-three 17th, but he's still some distance from the cup. McIlroy and Woods both find the middle of the green at the 15th, but Scott only catches the front and his ball spins back off.

Westwood, now five-over after another bogey at the 16th, gives himself an excellent chance of a birdie at the 17th by dialling an iron into the pin. Superb shot.

Scott plays a wonderful shot from just off the green and taps in for par. Woods eyeing up his birdie opportunity now...

It threatened to turn towards the hole but didn't quite have the legs. That should be par for Woods, who will remain at three-over. McIlroy (+2), from just a few yards further back, goes closer, but not close enough.

BIRDIE! Westwood gets back to four-over with a great two at the 17th. Meanwhile, Donald makes par to stay on three-under. They head to the difficult par-four 18th hole now.

Contrasting fortunes for Donald and Westwood off the 18th tee. Donald finds the fairway, but Westwood leaks a three wood into thick rough. He's all over the place at the moment. No doubt he'll be looking to get up that leaderboard, but he'll be well served keeping one eye over his shoulder. The cut mark looks like it'll be around five-over today, but that'll become clearer once the afternoon starters are into their second round.

Woods lands his second shot to the par-four 16th pin high, around 15 feet from the cup. McIlroy bombs his approach well over the pin and towards the back of the green. That should be a two-putt, at least...

McIlroy (+2) weights his putt perfectly to leave himself inches for his par. Very well judged. Scott's effort thinks about dropping, but horseshoes out of the hole.

Another well-judged putt, this time from Woods (+3), leaves him with a gimme for par. But that's not what he's after.

Russell Knox (-1) gets his second round off to a solid start with par at the first.

BOGEY! Westwood (+5) drops a shot at the 18th after another errant tee shot. After finishing his first round this morning with a 70, his second round has been woeful. He gave himself opportunity of a birdie at the 11th and three-putted for bogey. And it's got worse since then.

Donald makes his par to stay tied for the lead with Mickelson on three-under.

Scott (+2) isn't happy with his tee shot at the par-three 17th, but it lands on the green. Woods (+3) clubs down with a five iron, but doesn't get the result he wants, leaving it out to the right. McIlroy (+2), like Scott, goes with a four iron and can only find the front edge, before a slope takes the ball off the putting surface.

Matthew Goggin (-2) has opened his second round with two pars. He's in third on his own at the moment.

Woods (+3) chips from the green-side rough, McIlroy (+2) chips from the apron and Scott (+2) putts from distance... all leave a couple of feet for par.

BOGEY! McIlroy and Woods both tap in for par, but it's bad news for Scott (+3), as once again his effort loops out of the hole.

Great putt to save par from Westwood! He was in trouble off the tee once again, but recovers well to stay at five-over par.

Apologies, that putt from Westwood was for BIRDIE at the first hole. That gets him up to FOUR-OVER-PAR.

DOUBLE BOGEY! John Senden is fast approaching the more arduous back nine and already his round is starting to come apart at the seams. He bogeyed they eighth and he's now dropped two further shots to fall back to one-over-par.

BOGEY! KJ Choi, who birdied the first to get to one-under, is now one-over after back-to-back bogeys at four and five.

Billy Horschel is one-under through four holes today, putting him on one-over for the championship.

BIRDIE! Simpson gets to one-over by holing a testing putt from around five feet. He played excellently yesterday until play was suspended, but not so much this morning.

LEADERBOARD: (-3) Mickelson, Donald; (-2) Goggin; (-1) Knox, Colsaerts EVEN Clark, Schwartzel, Kelly, Day, Fowler; (+1) Senden, Simpson, Horschel, Matsuyama, Kim, D. Johnson, Watson, Stricker, Rose, Coetzee, Hoffman, Huh, Poulter, Stallings, Phelan

DOUBLE BOGEY! No sooner than I posted that leaderboard did Goggin drop two shots with a double bogey at the fourth. He is no even par through four holes.

BOGEY! Woods drops to four-over-par with a bogey at the 18th hole.

Donald (-3) plays a lovely bunker shot out of the trap on the par-five second hole. The former world number one made a mess of the hole by finding the rough with his third shot, but he doesn't have much left for his par.

Woods (+4) and Scott (+3) find the green at the first hole, but McIlroy (+2) is in the bunker.

Martin Kaymer has gone BIRDIE, BIRDIE, BIRDIE on the 18th, first and second to haul himself to three-over-par. His opening rounf of 76 had him well behind playing partners Donald (-3) and Westwood (+4), but he's now given himself a chance of climbing the leaderboard.

BOGEY! McIlroy played out from the bunker at the second hole, but hasn't managed to save par and he will now go back to three-over-par.

Scott (+3) didn't give his birdie putt enough break and misses the chance to get to two-under.

Only four players are under par at the moment, and two of them (Mickelson and Colsaerts) still haven't started their second rounds.

Donald (-3) goes to the right with his tee shot at the par-five fourth. Westwood (+5) finds the middle of the fairway.

STIFFED IT! Wonderful third shot from Tiger into the par-five fourth hole. That should be a birdie to take him to three-over-par.

Scott chops his ball out from the rough and runs quite a bit past the hole. McIlroy is also putting, but it's a tricky one.

Donald (-3) is juggling plates here, as his second shot from the rough at the fourth also finds the thick stuff a bit further down the fairway. He's scrambling...

BIRDIE! Scott (+3) and McIlroy (+3) both make par at the second, but Tiger joins them on three-over with a birdie thanks to a superb approach.

Donald is still struggling on the fourth hole. His third shot is also in the rough, leaving him with work to do to save par. Woods finds the green at the third.

WHAT A MESS Donald is floundering. His chip from the rough goes straight into the bunker in front of him. He's pitched out to within eight feet, but he's staring down the barrel of a six (or worse) on the par-five fourth.

BIRDIE! McIlroy gets back to two-over with a long birdie putt at the third for a two.

BOGEY! Donald (-2) ends up making a bogey six at the fourth hole, meaning that he has played both par fives in two-over. That's not good, by anyone's standards. But he's done well to stop the leak at just one shot on that hole.

Lee Westwood's second round has been, frankly, a nightmare. Birdies at the 17th and the first have offered little respite from six bogeys and one double, which has seen him drop from even par at the start of his round to six-over at the moment. He's in danger of missing the cut.

McIlroy (+2) is in trouble at the par-five fourth, slicing his drive to the right and landing in deep rough. He finds the fairway with his second shot and will have a look at the green for his third.

Woods (+3) gets his club tangled in the gnawing rough and it means his second shot leaves him with yet more work to do on the par-five fourth hole.

Only five players out on the course are under par, which is a testament to how difficult this course is playing. The lead is still with Mickelson at three-under, but it could well be over-par by the end of play today. The cut looks like it'll be somewhere around five-over.

Donald (-2) is in trouble again on the fifth. His tee shot was wayward and he was forced to take a penalty drop. His third shot finishes short of the green, so it looks like he'll be dropping even further back.

McIlroy (+2) plays his fourth shot from the bunker at the par-five fourth hole, but leaves himself a difficult one to save par.

BOGEY! McIlroy (+3) leaves his putt on the lip of the hole, and that means he's dropping a shot.

BIRDIE! Woods gets to two-over with a fantastic four at the par-five fourth. He was poor off the tee and his second shot left him in trouble, but his approach to the green was great and the putt matched.

Matthew Goggin and Russell Knox are both even par through six holes of their second round.

BOGEY! Apologies, my mind was elsewhere. Scott ended up making BOGEY at the fourth hole, which sees him fall to five-over-par. Quite a difference.

Let's put this confusion behind us with an updated leaderboard...

LEADERBOARD: (-3) Mickelson; (-1) Donald, Colsaerts; EVEN Goggin, Knox, Choi, Clark, Schwartzel, Kelly, Day, Fowler; (+1) Senden, Fdez-Castano, Horschel, Matsuyama, D. Johnson, Watson, Stricker, Rose, Coetzee, Hoffman, Huh, Poulter, Stallings, Phelan; (+2) Woods, Choi, Els, Stanley, Loar, Bettencourt, Mahan, Cink, Stefani, M. Thompson, Weir, Pan; (+3) Ogilvy, Kaymer, McIlroy, Simpson, Kim, Watney, Casey, Siem, Garcia, Harrington, Jocobson, Kim, Peterson, Doak, Sutherland, Van Zyl, Nelsen

Plenty of players within six shots of the lead at Merion. Mickelson still sitting pretty at the top.

McIlroy chips from the rough at the side of the green, leaving himself with a testing putt. Donald looks ready to drop at least one more shot after his chip from the front of the green finishes around 10 foot from the cup.

DOUBLE BOGEY! And Donald's round really is falling apart now, as he ends up dropping two more shots at the sixth hole. He is now one-over-par for the championship.

SAVE! Woods stays at two-over with a marvellous putt at the fifth hole to save par.

McIlroy follows Tiger into the cup and stays at three-over.

Woods (+2) with his second shot into the par-four sixth, hits a five iron onto the green. That's a good chance for birdie.

McIlroy (+3) from the rough, 200 yards out. He gets a great connection and finds the front apron. Good shot.

Scott (+6) from a similar position, and he finishes a few yards short of McIlroy. Again, a good shot from there, he'll have a pitch onto the green.

Donald (E) putting for birdie from distance on the seventh green, but leaves himself something for par.

McIlroy (+3) leaves his birdie putt inches from the cup, so that should be par. Donald (+1) three-putts the seventh and drops another shot in an up-and-down round.

BOGEY! Scott now drops to seven-over with another missed par putt from distance on the sixth green.

Woods (+2) doesn't put quite enough on his birdie putt on the seventh green.

McIlroy (+3) saves par.

Woods and McIlroy find the fairway with their tee shots at the par-four seventh. Donald's second shot into the par-four eighth lands on the green.

Phil Mickelson, still leading on three-under, is on the practice range now. He'll be happy with how things have panned out so far, but how much will the course affect his game today?

Woods loses his second shot on the seventh to the left of the green and will have a difficult pitch from the rough with the hole cut so near to the edge of the putting surface.

Donald and Westwood find the green in two on the par-four eighth, setting up birdie chances.

Donald (+1) and Westwood (+6) can't convert their birdie putts and stay where they are.

If we look at the bottom of the leaderboard, we see Olesen (+17), Furyk (+15), Cabrera (+15), D. Clarke (+14), F. Molinari (+11) and McDowell (+11). And remember Estanislao Goya, who challenged at the top of the board yesterday? Well he has carded six bogeys and three doubles on his second round, which sees him 14-over-par.

BOGEY! Woods (+3) drops a shot at the seventh to slip back alongside McIlroy.

I'll keep you posted with those challenging on the cut line, and what that cut line may be, throughout the course of the afternoon session at Merion. But with the second round almost certainly going on until tomorrow morning, who won't know definitively until then.

The afternoon session will be full of intrigue. The game has a different slant to it when the leaders are coming in rather than streaking in front. It's great drama watching the players scramble around the course. I've really got a feeling that the lead will be even par or over by the end of play today.

BIRDIE! Donald (E) gets back to level par thanks to a fantastic tee shot at the par-three ninth hole, which left him with a nice putt for birdie.

BIRDIE! McIlroy (+2) taps in for a birdie at the eighth. How low can he go on his final two holes?

Woods (+3) makes par at the eighth.

McIlroy's approach to the par-three ninth finishes short of the green. Scott, still at seven-over, hits a five iron that dribbles off the apron and onto the putting surface. Woods also takes a five iron, looks like he doesn't like it but he should, it finds the green and sets up a birdie chance.

Billy Horschel is currently two-under through 13 holes for his second round, which has him at even par for the championship. If he can keep his round going he's on for a great score.

McIlroy puts too much on his chip from the rough at the edge of the green on the ninth, leaving him with work to do for his par. Donald lands his approach to the 10th green on target.

Westwood (+7) is looking to get into the clubhouse, but is pitching from the bunker at 10. It's well played, but still work to do.

CLOSE! Woods (+3) sends a birdie putt towards the hole, it breaks late and drifts by the cup. It looked in all the way.

BOGEY! McIlroy (+2) gives a shot back at the ninth.

Lee Westwood has made par on the final hole and posts 77 for his second round, leaving him seven-over-par for the championship. It's dicey as to whether he'll make the cut or not.

Luke Donald finishes two-over-par for his second round, leaving him level heading into the weekend. He's been fighting an uphill battle after a great start faded, but he'll be happy with his score.

Others in the clubhouse include Peter Hedblom, who finished eight-over for his second round after coming in level for his first. Geoff Ogilvy is four-under, while his compatriot John Senden is one-over. That could be close to the lead soon enough.

Woods hits his tee shot at the par-four 10th safely onto the fairway. That'll give him a decent swing into the green. McIlroy also takes an iron to his, but finds the rough.

Luke Donald: "I was upset at the par fives, to make two sixes there. Some of the other bogeys, I felt like I hit good shots. The pins were very tricky, it was nice to get one back on nine. Overall, very satisfying over the first two days."

So Donald is the clubhouse leader on even par with Mickelson (-3) and Colsaerts (-1) about to get their second rounds underway.

McIlroy and Woods both find the green at the 10th.

Woods (+3) sends his birdie putt downhill towards the cup, but it doesn't reach and he taps in for par. That's a 73 for his second round, which puts him right in there come the weekend.

McIlroy (+3) also misses with his attempt at birdie and leaves himself a tricky one coming back, but manages to clean up for par. He's also at three-over and in contention, despite looking nowhere near his best.

Scott (+7) makes it a trio of misses and he finishes on seven-under, which means he'll be watching the cut line this afternoon.

No sign of nerves for Mickelson, who safely finds the fairway on the first hole. Stricker and Bradley also hit decent shots.

Click here to read of Donald and McIlroy's travails at Merion. It was a slog, but they're still in touch.

It seems I was watching someone else when thinking it was Mickelson. He put himself in trouble, but a decent second shot has him back in play.

BOGEY! Mickelson (-2) drops back to two-under on the first hole. He was out of position with his first shot and never properly recovered. That certainly makes things interesting.

Rory McIlroy: "It was solid. I got off to a good start, it felt like every time I made a birdie I made a bogey [straight afterwards]. It's tricky, [but] I'm right there for the weekend so I'm happy about that. This course tests you, I think something low under-par will win this week, if not over par."

The big-hitting Belgian Nicolas Colsaerts has driven the green on the par-four 12th, giving himself a chance of an eagle. If he makes that, he'll take the lead on three-under. A birdie will see him tie Mickelson at the top.

Mickelson pushes his tee shot at the par-five second into the rough.

BIRDIE! Colsaerts (-2) lags his putt inches from the cup and taps in for a share of the lead. Very well played.

Mickelson's second shot on the par-five second is swallowed by the bunker.

BIRDIE! Rose (E) gets back to level par with a birdie on the first hole. He judged his 20-foot putt to perfection, watching it drop into the bottom of the cup.

Mickelson lands his third shot on the green at the par-five second. That's a chance for birdie.

Clark (E) with his third shot into the par-four first hole, lands it cup-high but it bites back and leaves him with a difficult one for par.

BIRDIE! Stricker (E) gets back to level par with a good putt at the second.

Mickelson (-2) doesn't read the break in his birdie putt and stays in a tie for the lead.

Colsaerts (-1) was off the green with with tee shot at the 13th and ends up dropping a shot, dropping back behind Mickelson, who is once again in front on his own. Although the lead to Donald is just two now.

Rose (E) with his second shot at the par-five second, but he loses it to the right and it lands in the rough. Still with a chance of birdie.

Mickelson's tee shot into the par-three third finds the centre of the green.

Schwartzel (E) has got himself into some bother on the first hole and looks like dropping at least one shot there, so not the best start from the 2011 Masters champion.

Rose's third shot was actually from the bunker, and he's done well to land it one the green. That's a difficult birdie chance, but a birdie chance nonetheless.

Very good putt from Mickelson (-2) on the third green, leaving it within inches for par.

NEW CLUBHOUSE LEADER! Billy Horschel posts a one-under 67 to take the clubhouse lead by one shot over Luke Donald. That's some round from the American.

DOUBLE BOGEY! Schwartzel (+2) goes on the make a double at the first, dropping him back to two-over-par. He's heading to the par-five second now, where he will be hunting a birdie to get back on track.

Mickelson finally finds the fairway with his three wood on the fourth hole. Rose hits a five iron into the par-three third, hitting the green to leave a long one for birdie.

Schwartzel hits a stupendous shot into the flag at the second, leaving him with a short putt to get one of the shots back.

BIRDIE! Rose (-1) drains a 25-footer for birdie at the par-five second. His approach to the green, like Mickelson's, was sloppy, but he manages to convert a tougher chance to keep his early momentum going.

BIRDIE! Great response from Schwartzel (+1) as he taps in for a birdie.

Colsaerts (-1) sinks a good put to save his par at the par-five fourth to stay one behind Mickelson.

Rose (E) found the green at the par-three third, but sent his first putt wide. He held his nerve over a four-foot tester for par, though.

Matthew Goggin has posted a four-over 74 for his second round, leaving him two-over-par for the championship.

Mickelson (-2) rolls in for par at the fourth, meaning that he has played the two par fives in even par.

Rose's lay-up at the fourth finds the rough.

Mickelson's tee shot at the sixth flirts with the bunker but ends up in the thick grass. He is all over the place off the tee today.

Billy Horschel hit all 18 greens in regulation today, that's some going. He says that it doesn't surprise him, but I bet it does a little bit. Especially at the US Open, where the course is notoriously difficult, along with the added pressure of it being a Major championship.

LEADERBOARD: (-2) Mickelson; (-1) Horschel, Rose; EVEN Donald, Colsaerts, Stricker, Kelly, Day, Fowler; (+1) Senden, Schartzel, Poulter, Coetzee, Hoffman, Huh, Stallings, Phelan

BOGEY! Colsaerts (E) bogeys the par-four fifth after a poor approach into the green and he drops back to level par.

Rose (-1) sends a birdie putt wide on the fourth green and taps in for par to remain one behind Mickelson.

Poulter (+1) drags his tee short at the par-three third wide to the right.

Mickelson is in a spot of bother on the fifth after yet another errant tee shot. He's scrambling for par there.

Sergio Garcia (+3) starts his second round with three-straight pars.

Mickelson (-2) gets himself out of jail with a putt for par on the fifth. Colsaerts (E) plays a great shot from out of position on the sixth to leave himself a few feet from the cup.

Poulter (+1) saves par at the third after a poor tee shot.

Colsaerts stands over an eight-footer for par at the sixth and sinks it to stay level par.

Mickelson's second shot into the par-four sixth finds the green. He'll have a chance to get to three-under. Stricker (+1) takes a four iron into the green and lands it on.

BIRDIE! Jerry Kelly (E) gets himself level with a birdie at the second.

Rickie Fowler (E) hits a wayward tee shot at the par-three third and has to chip out onto the green, but catches it hot. He's now at the back of the green and will have a difficult two putt.

Rose (-1) makes a four at the fifth, but it looked as if his putt might just miss as he began to walk towards it... but it rattled down the tube.

Mickelson's birdie putt at the sixth slides by the hole and he stays at two-under.

Fowler (+2) three-putts the third hole and drops two shots. His tee shot put him in all sorts of trouble.

Mickelson (-2) finds the fairway with his tee shot at the seventh. Rose (-1) with his second at the sixth and that's a loose shot which spells trouble. He'll do well to get up and down there.

A brilliant shot from the rough from Rose leaves him with around eight foot for his par.

BIRDIE! Charl Schwartzel has got himself back to even par with another birdie at the fifth. He's recovered well from posting a double on the opening hole.

BOGEY! Rose (E) can't take advantage of his superb third shot by converting for par and he drops back to level.

BIRDIE! Colsaerts (-1) gets out of jail with a terrific chip shot at the eighth and he moves back under par.

A birdie opportunity goes begging for Poulter (+1) at the fourth.

Mickelson (-2) makes par at the seventh.

Colsaerts with his tee shot at the par-three ninth, loses it to the right. It's so far wide it misses the water and lands on a grass bank. Loose one from the Belgian.

BIRDIE! Rickie Fowler claws a shot back with birdie at the par-five fourth.

WHAT A SHOT! Mickelson's approach to the par-four eighth is something else. He loved it as soon as he hit it. That's an excellent opportunity to get to three-under-par.

Poulter (+1) hits his second shot into the par-four fifth hole, but finishes well short of the green.

Colsaerts took a drop after goes out of bounds at the par-three ninth and knocks his third shot close. It was a peach, but he'll be giving shots away.

MISS! Mickelson (-2) pulls his short putt at the eighth wide of the hole and has to settle for par. Golden opportunity goes by the wayside.

BOGEY! Colsaerts (E) sinks his putt at the ninth for a four, which drops him back to level par. But it could have been worse.

Another fantastic iron shot gives Mickelson a chance of birdie at nine. Can he take advantage this time?

BOGEY! Poulter (+2) gives away a shot at the par-four fifth.

BIRDIE! After getting back to level par at the fifth, Schwartzel (E) carded a bogey five at the sixth. A birdie at seven sees him back to even par, though.

MISS! Mickelson (-2) trickles his putt towards the hole on the ninth green, but it stays just on the edge and he misses another chance to get even for the day and stretch his lead at the top of the leaderboard.

BIRDIE! Rose (-1) gets back under par with a birdie at the eighth.

Colsaerts (E) sends his birdie putt just by the hole. Mickelson misses the fairway at the 10th.

Rose has a chance to card back-to-back birdies after a tremendous tee shot at the short par-three ninth.

Poulter (+2) with a long birdie putt at the sixth, it goes past the hole by around two foot. He rolls in for par, though.

Jerry Kelly is two-over-par through fives holes, Charley Hoffman is also through five and he is one-over. Jason Day is also at one-over.

Rose (-1) sees his birdie attempt at nine slip past the hole and he remains one behind Mickelson.

Colsaerts (E) with a birdie attempt at the par-four 11th, it's a good putt but slides by the hole.

Mickelson has missed chances to get to three-under-par at the eighth and ninth, while Rose has come close to tying the lead. Colsaerts also looks threatening, seeing long birdie putts just miss at 10 and 11.

The Belgian finds the rough with his tee shot at the 14th. Not a good drive.

Mickelson's approach to the 11th has some bite and clings to the green, giving him the chance to eye up another birdie opportunity. Surely he has to convert one of these...

Rose (-1) misses another chance for birdie at the 10th.

Colsaerts (E) made the green in three at the par-four 14th, but stays level after seeing his putt miss the hole.

Another chance goes begging for Mickelson (-2) at the 11th.

LEADERBOARD: (-2) Mickelson; (-1) Horschel, Rose; EVEN Donald, Colsaerts, Stricker; (+1) Senden, Schwartzel, Day, Phelan, Pan, Harrington; (+2) Goggin, Mahan, Poulter, Fowler, Hoffman, Kelly, Stallings, Stefani, Van Zyl, Weir

Padraig Harrington (+1) has snook up the leaderboard with birdie threes at the seventh and eighth.

Poulter (+2) hits a good shot into the eighth green to leave himself with a sight at birdie.

Rose (-1) with his second into the par-four 11th, lands it at the top of the green.

BIRDIE! Poulter (+1) sinks his putt for birdie at the eighth and gets back to one-over-par.

Mickelson finds the green at the 12th but it will be a bonus if he sinks it from that distance. I'm sure he'll give it a go.

It's par for Rose (-1) at the 11th and he stays one-under. It was a difficult putt and he knocked it to the edge of the cup.

Poulter finds the green with his tee shot at the par-three ninth. Colsaerts finds trouble with his first at the par-three 13th.

CLOSE! Once again Mickelson just misses with a putt to get to three-under. It broke from right to left and he nearly got it spot in. Close, but no cigar.

HOW DID THAT NOT DROP?! Poulter sends his putt towards the hole and it looks in all the way but catches the edge and bobbles out. Unfortunate. He stays three back.

In fact no, Poulter (+1) is just two shots back because Mickelson has three-putted the 12th, meaning he drops to one-under-par.

TIED FOR THE LEAD! That means we have a three-way tie between Mickelson, Rose and Horschel. Actually, no. Make that a four-way tie as Stricker picks up a shot to join them at the top of the leaderboard.

Mickelson (-1) fires too hard at the 12th green and skips off, plugging in the bunker. That's a nasty lie.

Rose with his second shot at the par-four 12th hole as he looks to grab the outright lead, he pitches above the flag and it feeds down a little, but that's a testing downhill putt.

Mickelson splashes out of the bunker and the ball flies past the hole. That looks like a dropped shot...

BRILLIANT SHOT! So nearly an eagle two for Colsaerts at the 14th, as he pitches the ball just before the hole, but it spins back and leaves him with a good opportunity to grab the lead.

BOGEY! Mickelson gives another shot away at the 13th. After missing a boatload of chances, he's now fallen out of the lead. He can;t let his head drop, though.

That leaves Billy Horschel, Justin Rose and Steve Stricker out in front on one-under-par.

Rose (-1) leaves his putt at the 12th short and he stays in a three-way tie for the lead.

Mickelson hits the fairway with his tee shot at the 14th, while Rose lands his on the green at the par-three 13th. He has a long one for birdie.

Brilliant shot by Stricker sees him on the green in two at the 14th and putting for a chance of birdie.

Rose (-1) sees another chance to take the lead slip by as his long putt at the 13th doesn't have enough on it.

Colsaerts (E) putting for birdie and a share of the lead at 15, it's got postcodes to travel and he leaves it short.

Stricker (-1) leaves his birdie putt on 14 to the right and he stays at one-under.

Mickelson (E) finds the cup to stop the bogey rot with a par at the 14th.

Stricker on the tee at the par-four 15th. He takes a three wood and lands it on the left-side of the fairway. Colsaerts (E) makes his par at the 15th and stays level.

Mickelson lands his tee shot on the left of the fairway, not far from Stricker's ball.

Rose from the fairway at the 14th, he finds the green with his approach and has another long look at birdie.

Stricker's second into the 15th green, it's safely on the front part of the green but it'll be a testing two-putt. Mickelson knocks his on the front as well.

Rose (-1) comes up short with his putt at the 14th and he remains one-under. Like Mickelson, Rose has missed chances, but his have arguably been harder. The putter has been in decent nick so far this week.

Colsaerts is on the green but miles from the cup at 15.

The greens have slowed a bit in the cover of the shadows and a few putts are being left short now. Mickelson and Stricker both leave themselves with work to do to save par.

Is anyone going to make a move before the end? Or perhaps more likely, who will fall out? Mickelson, Stricker, Rose and Colsaerts still have some way to go before the end of their second round, and let's not forget that we'll be finishing tomorrow morning.

BOGEY! Stricker (E) gives away a shot at the 15th and he's back to level par. Justin Rose and Billy Horschel share the lead, although the American is sitting safely in the clubhouse.

Mickelson finds the fairway at the 16th. Stricker follows him onto the short stuff.

BOGEY! Colsaerts (+1) goes to one-over now after pushing a putt past the hole for par at the 16th.

Harrington (+2) can't find a birdie at the par-three 13th but taps in for par.

Colsaerts is on the green at the par-three 17th but once again leaves himself with virtually the entire green to traverse.

Mickelson (E) leaves another one inches from the cup at the 16th.

Stricker (E) goes close at the 16th but he settles for par as well.

Rose (E) at the 16th tee now with an iron in hand, safely finds the fairway.

BIRDIE! Poulter sinks one of his classic putts to get to level par through 13 holes. He is one-under for his second round, brilliant stuff.

Rose's second at the 16th, safely locates the green. Colsaerts (E) rescues par at the 17th to stay level par.

Mickelson finds the green at the 17th but, like so many on that hole today, he has work to do to pick up a shot. Stricker's tee shot lands at the back of the green.

LEADERBOARD: (-1) Horschel; EVEN Donald, Mickelson, Stricker, Rose, Poulter; (+1) Senden, Colsaerts, Schwartzel, Hoffman; (+2) Goggin, Mahan, Harrington, Kelly, Stenson

Mickelson and Stricker both make par at 17 to stay even. Poulter tugs his approach to the left at the par-four 14th.

Rose at the par-three 17th, hits the green. He's been accurate onto the putting surface today but left himself distance often.

Mickelson bombs his tee shots down the 18th fairway.

Stricker takes a shorter swing but he too is safely on the fairway.

Rose (E) leaves his putt stone dead at the 17th and he'll head to the last even par and looking to hopefully tie the lead.

Nicolas Colsaerts (+1) posts 71 for his second round and enters the clubhouse one-over-par for the championship.

Stricker goes first off the 18th fairway, he takes a five wood to it but falls well short of the green. Mickelson steps up with a long iron, 225 yards to the green and he is on for birdie.

Rose's tee shot at the 18th finishes just inside the rough. Harrington's third shot out the rough at the par-four 15th is a beauty and gives him a chance of saving par.

Stricker plays a delightful pitch into the 18th pin and, after he does, the buzzer goes to signal the end of play for today. The players can finish the holes that they're on if they wish. If not, then they'll come back early tomorrow.

BIRDIE! Finally Mickelson sinks a birdie putt and it was probably his hardest opportunity. He's now at one-under. That's a timely boost heading into the weekend.

That's 72 for Mickelson on his second round, which ties the clubhouse lead with Billy Horschel at one-under-par for the championship.

Rose with his second shot from the rough at the par-four 18, he lands it well short of the green and it doesn't look like he'll be tying the led tonight.

Amateur Cheng Tsung Pan has finished the day even-par, but he still has nine holes of his second round to play. Still, quite a performance from the young man.

Rose is on the green in three at the 18th and putting for par.

Justin Rose salvages par at the 18th to post a one-under 69 for his second round. Despite missing a few chances, I bet he'll be pleased with that. He's just one shot off the lead heading into the weekend.

At the end of day two, it's Billy Horschel and Phil Mickelson leading the way on one-under-par. Luke Donald, Steve Stricker, Justin Rose, Ian Poulter and Cheng Tsung Pan are level par and chasing. Poulter still has holes to complete tomorrow morning, as does Pan.

LEADERBOARD: (-1) Horschel, Mickelson; EVEN Donald, Stricker, Rose, Poulter, Pan; (+1) Senden, Colsaerts, Hoffman, Kelly, Kim; (+2) Goggin, Schwartzel, Mahan, Stenson; (+3) McIlroy, Woods, Fernandez-Castano, Els, Bettencourt, Day; (+4) Ogilvy, Van Pelt, Loar, Knox, Harrington, Dufner, Coetzee, Siem, Huh, Karlsson; (+5) Langley, Stanley, Casey, Fowler, Lingmerth, Stallings, Stefani, Weir, Sutherland, Nelsen; (+6) Choi, Donaldson, Simpson, Matsuyama, Garcia, Khan, Van Zyl, Phelan, Hutchison, Weibring; (+7) Lawrie, Westwood, Pettersson, Scott, Kim, Watson, Kuchar, Cink, Manassero, Laird, Jacobson, Peterson, LaBelle II CUT

Thanks for joining us at Sports Mole and come back tomorrow for all the action from the third round of the 113th US Open at Merion Golf Club in Pennsylvania.