Danny Welbeck and Theo Walcott proved the difference on their return from injury, as their goals helped Arsenal to a 5-0 victory over Southampton at St Mary's Stadium.
A one-sided tie was as good as over halfway through, with two smart Welbeck finishes - the first rounding off a 16-pass move - being followed up by a strike from Walcott.
The former Saint added another couple in the final quarter of the match to put the icing on the cake, meaning a place in the fifth round of the FA Cup for the Gunners.
Relive how the 90 minutes of action unfolded with Sports Mole's live text coverage below.
Hello and welcome to Sports Mole's live text coverage of the FA Cup fourth-round meeting between Southampton and Arsenal at St Mary's. It is already shaping up to be a day full of shocks up and down the country in this competition, with Liverpool crashing out and Tottenham Hotspur looking likely to join them, and one more Premier League side could join them in dropping out over the next few hours.
The Saints head into this match on a real high, having booked their place in their first major final since 2003 - against, ironically enough, today's opponents - while the Gunners themselves have put together a run of wins in recent weeks and are still battling on three fronts in the second half of the campaign. Plenty to get through between now and kickoff, so let us check out some confirmed team news.
TEAM NEWS!
SOUTHAMPTON XI: Lewis, Martina, Stephens, Gardos, McQueen, Reed, Clasie, Hojbjerg, Sims, Isgrove, Long
ARSENAL XI: Ospina, Bellerin, Mustafi, Holding, Gibbs, Chamberlain, Maitland-Niles, Walcott, Reine-Adelaide, Perez, Welbeck
Starting with a look at the visiting team, manager Arsene Wenger has made a whopping 10 changes from the slender 2-1 victory over Burnley six days ago. The only survivor from that match at the Emirates Stadium last weekend is Germany international Shkodran Mustafi, who lines up in the heart of defence alongside fellow summer recruit - albeit at a far different end of the scale - Rob Holding.
The big news for Arsenal is that Danny Welbeck makes his first start since May after overcoming his latest injury problem, while Theo Walcott is also back in the side following a shorter layoff; his last outing coming against Manchester City on December 18. There is no Granit Xhaka due to suspension, of course, although it is unlikely he would have played anyway as Ainsley Maitland-Niles and Jeff Reine-Adelaide are among those to come into this much-changed side.
Welbeck will lead the line for Arsenal in the absence of Olivier Giroud, while Walcott, Reine-Adelaide and Lucas Perez will offer support from attacking midfield. The other player I have yet to mention is Alex Oxlade-Chamberlain, who will likely start slightly deeper alongside Maitland-Niles. It is a brave choice from Wenger to make so much changes - 10 in all from last time out - as we have already seen it backfire spectacularly in some other games this afternoon.
In terms of the hosts, Claude Puel has also made 10 changer - quite an advert for the FA Cup, this. Jack Stephens, who handled the pressure superbly in the absence of Virgil van Dijk at Anfield, is the only player to retain his place from that memorable night on Merseyside. That means a place in goal for youngster Harry Lewis, with Fraser Forster missing out on the squad entirely.
Despite making wholesale changes from Wednesday, this is not an entirely second-string Southampton lineup. Indeed, Shane Long starts up top fresh on the back from scoring the only goal of the second-leg tie, while Jordy Clasie and Pierre-Emile Hojbjerg add some midfield steel. Steven Davis and Oriol Romeu, two of the standout performers at Anfield in those defensive-midfield slots, both miss out.
Puel's hand was forced slightly due to injuries picked up by James Ward-Prowse and Jay Rodriguez a few days ago. There was also another impressive display in the first half from Nathan Redmond - another to be given a little breather as he is only among the subs. It will likely be a 4-4-2 system as far as the Saints are concerned, with promising Welsh talent Lloyd Isgrove among those looking to make the most of his chance in this fourth-round tie.
BENCH WATCH!
SOUTHAMPTON SUBS: Taylor, Yoshida, Bertrand, Davis, Romeu, Tadic, Redmond
ARSENAL SUBS: Martinez, Monreal, Mertesacker, Jenkinson, Iwobi, Sanchez, Gabriel
A case of Wenger making up the numbers when looking at the Arsenal bench, as four of the six outfield options are defenders. Alexis Sanchez and Alex Iwobi are among the back-ups if a goal is required in the second half, while Southampton can turn to the creative duo of Dusan Tadic and Nathan Redmond if required. Aforementioned duo Davis and Romeu are also in the squad.
Hardly the greatest advert for the FA Cup at St Mary's this evening, as both managers make 10 changes to their starting lineups. Southampton boss Claude Puel does have a bit more of an excuse as nine first-team players have been nursing injuries, with Jack Stephens the survivor from the 1-0 win at Anfield on Wednesday. Arsene Wenger keeps Shkodran Mustafi in Arsenal's ranks, meanwhile, as he opts to use his rotation policy yet again.
What was looking like being a season of mediocrity for Southampton could well turn into one of their finest in living memory. Six days ago there was talk of this being a huge week for the club, as they prepared to take on Leicester City (Premier League), Liverpool (EFL Cup), and Arsenal (FA Cup) across three separate competitions. So far, so good on that front, as the Saints have overcome the first two opponents and will now feel confident of making it a clean sweep.
Starting with that victory over Leicester - a thumping 3-0 scoreline reflective of their dominance - the Saints quickly laid down a marker to prove that they are not prepared to slumber in mid-table. Then came the famous win on Merseyside, sealed with a Long goal in added time just to give those travelling fans something extra to celebrate, which you have to say they were more than deserving of over the two legs.
As ever, there is now a risk of their eye being taken off the ball in the coming weeks as those Southampton players prepare to run out at Wembley Stadium against Manchester United. The Saints have between four and six games to play before then, though, depending on the outcome of today's result, so they cannot afford to take their foot off the gas. In fairness, the worst case scenario for Puel is finishing in the bottom half and reaching a cup final in his maiden campaign - a luxury Wenger cannot fall back on with defeat here.
The pressure had actually been building on softly-spoken Puel prior to this good run of form. A run of four-successive losses in the FA Cup, coupled with a late capitulation against Norwich City in the previous round of this competition, left fans wondering if they had finally brought a dud on board. That does not look like being the case, however, as the Frenchman has showed good tactical maturity and led his side to four wins in their last five in all competitions.
Southampton are essentially just jostling for position now in terms of the league aspirations, with any hopes of a top-six finish - and thus a place in the Europa League next term - surely all but over. There is always the backdoor route into the competition via these domestic cups, of course, which Puel will no doubt be looking to exploit. The Saints currently sit 11th in the table after returning to winning ways in the league last time out and are 14 points off United in sixth.
The Saints' season started to nosedive a little once they exited the Europa League in rather disappointing circumstances early last month; a stalemate against Hapoel Be'er Sheva here seeing their previous triumph over Inter Milan count for little other than precious memories. The good news is that all focus can go on prolonging their run in both cup competitions, with their final appearance in the EFL Cup possibly being added to by a place in the last 16 of the FA Cup should they overcome heavyweights Arsenal over the next couple of hours.
Southampton face Swansea City in midweek and West Ham United next weekend, before then tackling another struggling side in Sunderland. Should they progress this evening, a fifth-round tie is pencilled in prior to their EFL Cup final with Man United in the capital, so there is certainly plenty to keep supporters occupied over the next four weeks. In terms of their FA Cup story to date, the Saints overcame Norwich in a replay recently thanks to a late Long goal on the south Coast.
Puel's charges have quite some record this term when it comes domestic cup games, having won six and drawn one; the anomaly in that run coming in a 2-2 tie at Carrow Road at the start of the month which they soon made up for in the replay. Their Euro form was a little more mixed; two wins, two draws and two defeats seeing them exit at the group stage. Now there is the chance to keep their season alive on two fronts - three including their outside hopes of breaking into the top six - but they face a real daunting task at St Mary's.
A season that was heading for mediocrity just a week ago could now turn into one of the most famous in Southampton's proud history. The Saints beat Leicester City a week ago to put a poor run of Premier League form behind them, before picking up a famous win at Anfield three days later to make it into their first cup final of any sort since 2003. Their opponents that day? Today's fourth-round visitors Arsenal.
RESULTS! Time to bring you up to speed with some full-time results from across the country now. Liverpool crashed out at the hands of Wolves in the day's early kickoff, but Spurs avoided a major scare as they scored in the 97th minute to earn a 4-3 win over Wycombe at White Hart Lane. No such trouble for Chelsea and Man City, who are also into the hat for round five thanks to wins over Brentford and Crystal Palace respectively. Big mention for Lincoln, too, who progressed with a 3-1 triumph over Brighton.
Arsenal will be looking to become the latest Premier League side to make it through unscathed following what has largely been an impressive season to date. It is always difficult to measure just how successful a season it has been for the Gunners until that final curtain comes down, as so often they have looked good before fading - or indeed vice versa, as witnessed last time around when somehow overtaking Spurs to finish second in the league.
What is clear is that Arsenal have often relied on the FA Cup in recent seasons to keep supporters happy - just about! This is the only competition won by Wenger in the past decade, essentially keeping him in the job because their record in the Premier League and Champions League has simply not been good enough. The cynic would suggest that this is their only hope this term, too, as Bayern Munich are next up in Europe and Chelsea have an eight-point lead in the top flight.
DID YOU KNOW? Arsenal were knocked out of the EFL Cup at the quarter-final stage by Southampton thanks to goals from Jordy Clasie and Ryan Bertrand in the first half, and they also pushed Arsenal all in the way in their league meeting, only for Santi Cazorla to snatch the points with a 94th-minute penalty. Victory today would make Puel's men the first side to knock the Gunners out of both domestic cup competitions since Manchester United in 1982-83.
Arsenal's form has been solid enough this term, with just three defeats in 31 since the opening day. All of those came in the space of a month, too, including back-to-back away league defeats at the hands of Everton and Manchester City to see their title hopes take a major blow. The good news is that the Gunners face leaders Chelsea next weekend, while the Blues also take on fellow contenders Liverpool in midweek. If things pan out the way supporters - and indeed neutrals - wish, that gap could be down to two points by the end of next weekend.
Arsenal beat Preston North End in the last round to make it this far, but it required a last-gasp goal from Olivier Giroud - adding to Aaron Ramsey's earlier leveller - to get the job done. The Gunners have incredibly lost just four of their 20 fourth-round ties under Wenger, the last of which came in 2010 when slipping to defeat at Stoke City. They have also won five away FA Cup ties in a row, yet a sixth has eluded them throughout their history - a chance to put that right today.
PREVIOUS MEETINGS! Southampton have kept clean sheets in four of their last six meetings with Arsenal in all competitions. This is the first FA Cup tie between the two sides since their 2003 final in Cardiff, which the Gunners won thanks to Robert Pires's only goal of the match. They have faced off on two other occasions in this famous competition; Arsenal coming out on top in both 1927 and 1979.
With kickoff on the South Coast now less than five minutes away, lets us turn attention to some pre-match thoughts from both camps.
Claude Puel: "It's important to put this experience for next year in European games. It'll be important to qualify. It will be important for the squad to continue the work, to improve, and know the possibilities to play European games.Now we go to Wembley, not just to participate but to win this cup."
Arsene Wenger: "[Late goals] is a very interesting quality in the squad. On top of that, the contribution of the players coming off the bench this season has been absolutely remarkable. That shows you as well that there is a great unity in the team. These are qualities that will be very important going into the last four months now."
Both sets of players are out on the field of play, with kickoff at St Mary's Stadium now a couple of minutes away. A reminder of the team news for you - 10 changes apiece for Arsenal and Southampton. Shkodran Mustafi and Jack Stephens are the only survivors for their respective sides, which is all the more surprising in the visitors' case as they have had nearly a week off.
KICKOFF! Southampton, sporting their traditional red and white stripes, get us up and running at St Mary's Stadium. Arsenal, without manager Arsene Wenger on the touchline today, are in their yellow and black away kit.
An early half-chance for Reine-Adelaide, who got on the end of a cutback but could only send his deflected shot wide of goal. Prior to that, Long pulled up with what appeared to be a hamstring strain but seems OK to continue.
Perez gets himself in a promising position inside the box, only to send his flashed cross straight through. Welbeck was unhappy with his teammate, pointing to the spot where he wanted the ball played. Good start for the visitors.
Arsenal finding plenty of gaps in these early stages, with Reine-Adelaide laying the ball of for Oxlade-Chamberlain to drag wide of goal. A couple of early shot for the Gunners, neither of which have tested Lewis between the sticks.
Mustafi, the one survivor from last time out, does well to get into an awkward position and head the ball away before Long could get to it. The visitors dominating this game so far but have yet to test rookie keeper Lewis.
Southampton giving away the ball far too easily in midfield, which is giving Reine-Adelaide in particular a chance to capitalise. Bellerin is in a good position but his cross was rather poor and collected by Lewis with ease.
The Gunners are really enjoying themselves in the opening 12 minutes, but I'm sure Wenger - high up in the stands - will want to see an early goal to settle those nerves a little. Southampton still yet to get going.
GOAL! SOUTHAMPTON 0-1 ARSENAL (DANNY WELBECK)
Right on cue, there is that breakthrough goal for Arsenal. They have been on top from the off, really getting in their opponents' faces, and this was a fine team move to edge ahead. A passing move ended with Perez slipping in Welbeck, who found the net via the crossbar.
No sign of Arsenal letting their dominance of possession change hands despite that goal, as they are now in search of a second. Appears to be a lack of bite in that Southampton midfield, even if they do have Clasie and Hojbjerg in their ranks.
A first start for Welbeck in 265 days is capped with that impressive finish. Wenger's risk to give some of his fringe players a run out is working fine at the moment, as the Gunners are sitting pretty on their lead.
GOAL! SOUTHAMPTON 0-2 ARSENAL (DANNY WELBECK)
The visitors have themselves a second and are well on course for a place in the last 16 of the FA Cup. A ball over the top from Oxlade-Chamberlain was latched on to by Welbeck, who then scuffed the ball under the body of Lewis to double his personal tally.
SHOT! Ospina has had nothing to do all evening until now, but his decision making has to be questioned on this occasion. The South American raced out and got nowhere near the ball, allowing a cross to come in for Hojbjerg who blasted over the bar.
SAVE! Well that second Arsenal goal has finally sparked some sort of response from Southampton. Martina sent an inch-perfect ball around the back for Long to chase down, and the Irishman's belter required helping over by Ospina.
That is the first brace that Welbeck has scored in the FA Cup, while six of his last seven in the competition have now come away from home. This is quite some impact from the Englishman, who is proving why he is so highly regarded by Wenger.
CHANCE! It should be game over. Mustafi, fresh on the back of his first goal against Burnley a week ago, glances wide from a free kick just a few yards from goal. Arsenal will unlikely need a third at this rate, though.
A far more balanced game since Arsenal went two ahead, but Wenger will not mind that at all. Long is nudged in the back by Gibbs 20 yards from goal - just outside the box - and the Saints have a good chance to pull one back.
Hojbjerg sends the free kick into the side-netting. A good technique from the Dane, but it did not have enough whip on it to trouble Ospina. Better from Southampton over the past 10 minutes, though the damage may have been done.
GOAL! SOUTHAMPTON 0-3 ARSENAL (THEO WALCOTT)
Game over at St Mary's with half time still eight minutes away. Perez and Welbeck link up well, with the latter able to keep his composure and pick out Walcott to prod home a killer third for his side. Shocking defending from the hosts.
Clasie sums up Southampton's half by scuffing a shot wide from 25 yards out. The Saints were superb in midweek all over the pitch but these 10 changes have clearly cost them; this is one competition they will not partake in beyond January.
A scrappy period in midfield, but it is Isgrove who comes out on top as he spreads it out to Hojbjerg. The ball is a decent one though Ospina got there first to collect the ball ahead of Long. The Irishman has had very little service so far.
Sims finds the ball at his feet five yards from goal, albeit at a tight angle, but he can only wriggle his way so far out of danger when closed down. A vast improvement required from the Saints in the second half if they are to have any hope.
A couple of minutes added on at the end of this first half; a one-sided first half that Arsenal have dominated. Two goals from Welbeck and one from Walcott has them essentially in that proverbial hat for round five.
HALF TIME: SOUTHAMPTON 0-3 ARSENAL
Arsenal are flying the midway point, as they take a three-goal lead into half time. Danny Welbeck got the party started with a couple of goals of his own, before Theo Walcott prodded home from close range after being picked out by his compatriot. Forty-five minutes to play but this one is as good as over already.
There was a sign of things to come for the hosts pretty much from the off, as the lively Jeff Reine-Adelaide and Alex Oxlade-Chamberlain were both picked out in good positions inside the opening five minutes. Neither player could make their shots count, but Danny Welbeck had no such trouble soon after as he rounded off a 16-pass move by finding the net via the crossbar to put Arsenal ahead.
A second for the Englishman was not long coming, either, as he this time latched on to a ball over the top from Oxlade-Chamberlain and rather scuffed his shot under the body of Harry Lewis. That finally sparked some sort of response from Southampton, who saw a Shane Long strike helped kept out David Ospina and Pierre-Emile Hojbjerg volley over the bar from a good position.
The Gunners may have taken their foot off the gas slightly but, moments after Shkodran Mustafi - the one survivor from last time out - glanced wide from close range, Theo Walcott prodded the ball home after being picked out by two-goal Welbeck. Arsenal lead by three goals at the break, then, with Southampton now essentially trying to keep the deficit down. Here is a reminder of both teams' subs...
SOUTHAMPTON SUBS: Taylor, Yoshida, Bertrand, Davis, Romeu, Tadic, Redmond
ARSENAL SUBS: Martinez, Monreal, Mertesacker, Jenkinson, Iwobi, Sanchez, Gabriel
RESTART! Arsenal get us back up and running in the second half of this FA Cup fourth-round tie, aiming to simply see things through. It has been very simple for the Gunners thus far, but surely they will face more of a challenge over the next 45 minutes?
No changes made by either manager at the break, incidentally, which is not all that surprising. Puel will unlikely want to throw on Redmond and Tadic with the tie essentially over, while Wenger is more than happy with the way things are going.
Ominously for Southampton, their opponents have clicked into gear early in this second half and are in search of a fourth. Maitland-Niles had a good chance to do exactly that, only for his shot to rise high over the bar.
Ospina again collects the ball well, much like in the first half when getting ahead of Long. Bar a shaky moment when racing for the ball half-hour in and failing to get it, the Colombian will be happy with his shift so far.
SAVE! Another free-flowing Arsenal move, which this time ends with Perez picking out Bellerin inside the opposition box. The full-back's shot was hit well enough but Saints keeper Lewis got down well to keep the ball out.
Walcott initially does well but he appeared to lose his footing before he could square it for Perez. The Gunners fast closing in on that fourth goal of the match on the South Coast, which really would be the icing on the cake.
A good run from Sims down the left, but Maitland-Niles was back to cut out the cross for a corner. Southampton's best spell of the half ends with the set-piece coming to little, as Arsenal clear their lines to protect this three-goal cushion.
Reine-Adelaide picks up a knock and is a little groggy, forcing Ospina to throw the ball out of play. The youngster did not need any treatment, though, which leaves home fans understandably frustrated. An hour played at St Mary's and still no signs of a change.
This one is turning into a bit of a touch watch for the neutral, as the Gunners are so comfortable at the moment. It was a similar story in games involving Man City and Chelsea today - not so Spurs and Liverpool.
Just the one shot on target in this second half - Bellerin testing Lewis with a simple enough effort. Things could get worse for Southampton - Alexis Sanchez is being readied to come on for the visiting side, with 25 minutes to go.
SUBS! Dusan Tadic and Nathan Redmond are on for Lloyd Isgrove and Shane Long, while Alexis Sanchez replaces two-goal Danny Welbeck for the Gunners. Three big talents being introduced, but can any of them make an impact?
Clasie sends the ball high and wide when he perhaps should have been doing better, but the good news is that Tadic and Redmond played a part in the build-up to that shot. Play likely to be further broken up as it looks like Mertesacker is coming on.
GOAL! SOUTHAMPTON 0-4 ARSENAL (THEO WALCOTT)
They were on the end of a 4-0 thrashing here the last time they visited in late 2015, but Arsenal are well on course to avenging that as they have added another to their tally. Walcott was on hand to sweep home a low Sanchez cross.
ARSENAL SUB! If it wasn't over beforehand (it was), then it certainly is now with that second from Walcott. Clasie sends yet another attempt over the bar, as he fails to learn from previous attempts. Iwobi on for Reine-Adelaide.
Had this defeat come this time last week serious questions would have been asked of Puel. The Frenchman has since seen his side beat Leicester and Liverpool, though, and he is not under any real pressure as a result. Still, not a great evening for him!
Not the worst of attempts from McQueen, whose shot ends narrowly wide of the far post - Ospina had it covered, regardless. A tad more urgency from the hosts over the past few minutes but it is too little, too late.
We are now approaching the final 10 minutes and it is Southampton who want to hear that full-time whistle. Trailing 4-0, it has been a real disappointing evening for the Saints hot on the back of a wonderful display in midweek.
Walcott has now taken his tally to six goals in four away games in the FA Cup, incidentally - quite some going. A sixth-successive away win in the competition awaits Arsenal, bar the most incredible of comebacks from the Saints.
GOAL! SOUTHAMPTON 0-5 ARSENAL (THEO WALCOTT)
It seemed almost inevitable, didn't it? Walcott bags a hat-trick on his return to action against former club Southampton, getting on the end of a nicely weighted Sanchez pass and tucking past Lewis, who perhaps could have done better.
SAVE! Lewis is left exposed by Perez, but he did well to keep out his opponent by making himself big and stopping the one-on-one attempt. Once again, the long ball catches the Saints completely out as they pray for that final whistle.
Still would not bet against Arsenal getting that sixth, which would reflect just how one-sided this contest has been. Wenger has made his way for the dressing room, clearly confident that the win is secured. I think he might be right.
Just the two minutes of added time to come - referee Kevin Friend clearly feeling sympathy for the hosts because we have seen two goals and four subs in this second half. Walcott and Welbeck done the damage on the night; this match long but over.
FULL TIME: SOUTHAMPTON 0-5 ARSENAL
Referee Kevin Friend blows for full time, meaning a place in the last 16 of the FA Cup for Arsenal. It was game over by half time, in truth, as Theo Walcott added to two earlier Danny Welbeck finishes to put the Gunners three goals up midway through. Southampton failed to find any sort of response, with Walcott adding two more in the final quarter of the match to seal a comprehensive 5-0 win.
That concludes Sports Mole's live text coverage of events at St Mary's Stadium. An on-the-whistle report can be found by clicking here, while reaction from this and all the day's other FA Cup fourth-round ties can be found elsewhere on the site in due course. Thanks for joining!
