Good evening! Thank you very much for joining Sports Mole for tonight's FA Cup fourth-round replay as Manchester United look to avoid one of the biggest upsets in the competition's history at home to League Two outfit Cambridge United. Nothing could separate the two sides in a goalless draw at Abbey Stadium 10 days ago and, while the visitors may be hard-pressed to hold their more illustrious opponents again tonight, the fourth round has already thrown up a string of unexpected results. Let's start with a look at the two teams...

MANCHESTER UNITED STARTING XI: De Gea; McNair, Smalling, Evans, Rojo; Blind, Fellaini; Mata, Rooney, Di Maria; Van Persie

MANCHESTER UNITED SUBS: Valdes, Jones, Valencia, Herrera, Young, Falcao, Wilson

CAMBRIDGE STARTING XI: Dunn; Tait, Taylor, Coulson; Donaldson, Champion, Elliott, Chadwick; Nelson, McGeehan, Simpson

CAMBRIDGE SUBS: Miller, Norris, Gaffney, Morrissey, Ball, Taylor, Kaikai

What can we make of those two sides, then? Well, the clearest thing from a Manchester United perspective is that Louis van Gaal has named a strong starting XI as he looks to avoid a monumental upset tonight. Wayne Rooney, Angel di Maria and Van Persie all start for the hosts, while Radamel Falcao is waiting on the bench should he be needed. The Dutchman is certainly taking this game seriously.

Van Gaal has made a few changes at the back in particular, though, with McNair, Smalling and Evans all returning to the side having missed out against Leicester, and indeed in the first tie against Cambridge. Rojo is expected to shift from central defence out to the left, while either Smalling or McNair will operate on the right flank. De Gea, meanwhile, keeps his place in goal despite Victor Valdes's presence on the bench.

Juan Mata and Marouane Fellaini come into the side from the victory over Leicester at the weekend, with the latter having also started at Abbey Stadium 10 days ago. Adnan Januzaj is one of those to make way despite a decent performance against the Foxes in midweek, with United holding on to the youngster amid plenty of rumoured interest on transfer deadline day. Rooney is expected to operate in the hold behind Van Persie, who starts having scored on Saturday.

Cambridge, meanwhile, make two changes to their starting lineup from the weekend's defeat to Luton Town, with Simpson and Chadwick coming in for Ball and Kaikai, who both drop to the bench. It is also two changes from the side that held United in the initial tie, with Dunn - who made a couple of vital stops in that match - retaining his place in goal as expected. Ryan Donaldson had been a doubt with a knee injury, but he has been passed fit to play.

The match will be a particularly special occasion for Luke Chadwick, who lines up for Cambridge tonight having begun his professional career here at Old Trafford. He won a Premier League title with Manchester United and saw a decent amount of first-team action under Sir Alex Ferguson before his departure. He was likely never expecting to play at the Theatre of Dreams again, so this will be a big bonus for the midfielder.

Of course, Manchester United come into this match as massive favourites to progress, and there are many reasons why Van Gaal is taking this competition seriously. Chief among them will be his desire to claim silverware in his first season at the club, but that goal looks a lot more achievable given the other results from the fourth round. It says a lot that Manchester United being held by Cambridge on Friday night was quickly forgotten due to events on the Saturday, with Bradford and Middlesbrough in particular contributing to an incredible day of FA Cup action. With Chelsea, Manchester City, Southampton, Tottenham and more all out of the competition, United will see this as a great chance to finally win it again.

For a club of United's stature, the wait has been too long for another FA Cup crown to add to their joint-record haul of 11. They last lifted this trophy in 2004, beating Millwall in the final, and the 11-year gap that has followed is the longest they have gone without winning the FA Cup since a 14-year wait between 1962-63 and 1976-77. Their failures in this competition have gone a little under the radar due to other successes under Ferguson, but since his retirement it has been highlighted a little more.

They will gain confidence from knowing that they are the best-placed team still in the competition, particularly for tonight's match, where they take on the lowest ranked team still in the Cup. Manchester United moved up to third in the Premier League table with a comfortable victory over Leicester City on Saturday, with Robin van Persie, Radamel Falcao and a Wes Morgan own goal giving the Red Devils a three-goal lead at half time. Wasilewski grabbed a consolation back for the Foxes, but United were never in danger of letting the lead slip like they did in the 5-3 reverse defeat.

That saw them return to winning ways at Old Trafford having lost their last home match 1-0 to Southampton. Overall, their record in front of their own fans has been very impressive, though, with only Chelsea boasting a better one in the Premier League. United have lost just once at home since the opening day of the season, winning nine of their 11 outings, with the only other exception being a 1-1 draw with Chelsea.

Overall, their form coming into this match stands at just one defeat in their last 15 games in all competitions, a run that stretches back to their derby defeat at the start of November. That includes a 2-0 victory over Yeovil in the third round of this competition - a match that needed moments of quality from Ander Herrera and Angel di Maria to finally kill off a spirited challenge from the Glovers at Huish Park. Their last FA Cup match at home saw them dumped out in the third round by Swansea last season, but before that they had gone seven home FA Cup games unbeaten, including six victories.

The hallowed turf of Old Trafford is certainly new ground for the vast majority of these Cambridge players, and it will make a welcome difference from Kenilworth Road, where they played at the weekend. They fell to a 3-2 defeat in their rather less glamorous surroundings on Saturday, failing to overturn a three-goal deficit at the break. They did almost launch a comeback, with Hunt and Simpson both coming off the bench to score, but they couldn't quite complete the job.

That result saw Cambridge drop to 14th in the League Two table, and they now sit exactly equidistant between the playoff places and the relegation zone. They are also now three matches without a victory, although the loss to Luton was their first in six outings in all competitions. They have won three of those and drawn two including, of course, holding Manchester United at Abbey Stadium 10 days ago.

While they understandably drew a blank against United, who have the third-best defensive record in the Premier League, Cambridge certainly know where the goal is. Despite their relatively lowly standings in League Two, only Northampton Town have scored more than Richard Money's side in the division this season. They have found the back of the net 42 times in their 27 outings, while only three teams outside the top five have conceded fewer than Cambridge's 33 goals.

One concern for Money will be his side's away form, particularly if he harbours any realistic hopes of getting anything from this game tonight. They have been inconsistent on their travels all season, winning five but losing eight of their away games. Four matches have also ended up as draws, and you'd have to think that they would be delighted to hold United again tonight. If they can hang on to penalties then anything can happen, but that in itself is a huge ask for the visitors.

This is already Cambridge's sixth FA Cup match of the season having needed a replay to get past Mansfield Town in the second round. They have dispatched of Fleetwood, Mansfield and Luton Town in the competition so far, reaching the four round and setting up this dream tie with United. Cambridge's best performance in the FA Cup is a couple of quarter-final showing in consecutive seasons, but they haven't managed to equal that since the early 1990s.

PREDICTION: We're just under 10 minutes away from kickoff at Old Trafford, which means that it is time for a prediction! Cambridge will give everything on what will be the biggest day of the career for many of their players, but I just can't see past a comfortable home victory tonight. We have already seen this season that nothing can be taken for granted in the FA Cup, but United have been imperious at home this season and, with a strong side, should cruise into the fifth round. I'm going for 3-0 to the hosts.

The winner of this match tonight will go on to face Preston North End of Sheffield United in the fifth round, and that is a match both would be fairly confident of winning. United would, of course, fancy their chances against League One opposition and that would leave the path even clearer for them to make it all the way to Wembley but, should Cambridge pull off an incredible upset tonight, then they will also believe that they could beat either Preston or Sheffield United to reach the quarters.

If Cambridge fans want a nugget of information to provide a bit of optimism, try this one out: today's visitors have not conceded an away goal in the FA Cup since 2011, when they lost 2-1 to Wrexham. It is fair to say that none of their three trips away in this competition have been as daunting as tonight's though, with victories over Needham Market and Macclesfield coupled with a draw against Bury.

As for United, if they get into a fairly comfortable lead in the early stages of the second half, don't be surprised to see Van Gaal protect some of his key players. The Red Devils have a tricky trip to face West Ham United at Upton Park on Sunday and, although the Hammers had slipped a little away from European contention in recent weeks, they are still enjoying a fine season and will pose problems for Van Gaal's side.

DELAYED KICKOFF: Old Trafford is very empty at the moment because a number of people have been caught on the motorway. As a result, the kickoff has been delayed until 8.05pm.

There are two other FA Cup replays taking place tonight, and I will keep you up to date with the major events from both of those games as and when they happen. Both Manchester United and Cambridge will have one eye on the result between Sheffield United and Preston.

Due to the delayed kickoff, the United side has come out to warm up again here. There can be no excuses for the hosts tonight, but they have been very respectful of Cambridge in the build-up to this match.

Van Gaal has just labelled the FA Cup as his number one priority this season, having won a number of domestic cups around the world already. None of these Manchester United players have won the FA Cup with the Red Devils, and they may not get a better chance than this season.

Is there any chance for Cambridge to pull off an upset here? Well, they will certainly take confidence from their performance at Abbey Stadium 10 days ago. They had chances to win that match in front of their own fans, but they will also be aware that they needed to hold on at times.

The supporters' coaches have now arrived at Old Trafford, so the ground should begin to fill up shortly. We are now a little over 10 minutes away from the revised kickoff time.

Cambridge are on their way back into the changing rooms having had a warm-up of their own to keep things moving during the delay. What an occasion it is for the League Two players tonight. They may never play at such an illustrious venue again, so they will be desperate to make the most of it tonight.

Richard Money will be telling his players simply to enjoy this occasion tonight. Very few people will be expecting the visitors to get anywhere near a positive result in this match, but the priorities for Cambridge will be not to get embarrassed and to savour the occasion.

More than 6,000 Cambridge fans have made the journey to Old Trafford tonight, showing incredible support for their side. As always, the away supporters are stuck up in the corner of the stadium, but they are doing their best to make their voices heard.

In the build-up to this match, Sports Mole spoke to Cambridge's Michael Nelson about his side's chances tonight. You can read that full interview here.

The players are out on the field and we are just a minute or so away from the delayed kickoff here. Can Cambridge upset the odds?

KICKOFF: Around 20 minutes later than scheduled, we are finally underway at Old Trafford! The hosts kick us off as they look to safely make it past this potential banana skin.

OFF THE POST! Oh my word, Cambridge are inches away from taking the lead inside the first minute! It is terrible play from Blind as he passes the ball straight to Elliott, who suddenly finds himself through on goal. With only De Gea to beat he tries to curl one into the bottom corner, but it hits the outside of the post.

What an incredible start that would have been for the League Two side. How costly could that miss prove to be, though? It is unlikely that they will get many gifts that like tonight.

Interestingly, United look to have started this match with Fellaini playing alongside Van Persie up front. Rooney, who was expected to be in a central role, is out on the right.

United have quickly gained control of this match after that early scare, controlling the ball and knocking it about inside the Cambridge half at will. A couple of crosses have been dealt with so far as the visiting defence holds firm.

UPDATE: The first FA Cup goal of the night has gone in at Craven Cottage, and it is Championship Fulham who are leading Sunderland of the Premier League. Hugo Rodallega got the opener shortly before the half-hour mark.

The hosts give a couple of really careless passes away in quick succession. They don't come to anything, but it is perhaps a sign of complacency and will certainly give Cambridge a bit of a boost. United simply need to concentrate tonight and they should be fine.

A cross into the Cambridge box at the back post, and Taylor looks favourite to cut it out before getting a subtle nudge from Rooney. The United skipper gets his head to it, but his effort to get it back into the danger zone deflects off Taylor and into the arms of Dunn.

Rooney plays a pass across field for Di Maria, whose first touch makes the ball sit up invitingly for a volley. He completely scuffs his attempt, but the ball almost falls for Van Persie before Coulson cuts it out.

The pressure from the hosts is beginning to slowly build here, and one notable aspect of their early play is the amount of crosses they have hoisted into the box. They have put it in the mixer at every available opportunity, but so far Cambridge have coped.

Good work from McGeehan as he quickly closes down Rooney, who looked to have a bit of space on the edge of the box. The Cambridge man slid in on the England skipper and got the ball to clear the danger.

SAVE! Dunn has his first save of the match, but it is a simple one for the Cambridge keeper. Rooney collected the ball on the edge of the box and cut inside onto his left foot before drilling a low effort straight at the keeper.

This is a concern for Di Maria, who stays down following a late challenge from McGeehan, who caught him with his studs. United certainly won't want any injuries in a match like this, but the Argentine looks like he should be alright to continue.

UPDATE: Cup specialists Sheffield United have drawn first blood in their replay with Preston, with Jamie Murphy breaking the deadlock at Bramall Lane. Remember, the winner of that tie will face the winner of this one in the fifth round.

United look to work something a little different as Di Maria drops the ball off to Mata before racing into the box. Mata puts a delivery in towards the Argentine, but he can only help it on past the post.

Bright play from Tait down the right flank as he knocks the ball past one defender and races on to it. He then tries to beat Blind, but Evans comes across to mop things up on a rare foray forward for the visitors.

The hosts make the breakthrough as one of their many crosses into the box finally pays off. Mata works the ball out wide to Di Maria, who hangs his cross up towards Fellaini at the back post. The big Belgian towers over his full-back and nods it down into a dangerous area, where Mata is waiting to flick in from close range.

So, Cambridge's resistance is finally broken after 115 minutes of this FA Cup tie. Is there any way back for the League Two side now? Well, they have already squandered one glorious chance and, if they are to come back from this one, they can't really afford to concede another goal here.

United are in complete control of this one at the moment, dominating possession and dictating the tempo of the match. They would like a second, ideally before half time, to make things even more comfortable, but that looks like only a matter of time right now.

CHANCE! A chance for the hosts to double their advantage as Di Maria races down the left and cuts the ball back for Mata, who completely mis-hits his shot when he should have done better. The ball is cleared as far as McNair, whose vicious low volley is deflected behind by McGeehan.

The hosts do get their second goal, and it is Rojo who opens his account for the club. A corner finds Fellaini criminally open inside the box, and the Belgian has time to chest the ball down and shoot. His effort deflects to Van Persie, who clips a cross in with the outside of his boot that Rojo nods home.

Poor old Cambridge may already be beginning to wonder 'What if?' Had Elliott scored that early chance then they would have had something to really defend, but since that scare United have been in cruise control. It is very hard to see the visitors recovering from this, but then we thought that about Bradford when they were two down against Chelsea!

SHOT! United go in search of a third as Mata cuts inside from the left flank before playing a square pass to Di Maria. The Argentine looks to curl a first-time effort in from 25 yards, but his effort is too high.

The hosts look to break quickly following a Cambridge free kick, with Smalling striding forward from defence. He tries to bend a pass around the last defender for Di Maria, but Dunn is quick off his line to make the interception.

In truth, United look capable of attacking at will right now and Cambridge may be starting to worry how many goals they will be on the end of tonight. They could well go into damage limitation mode after the break should this get any worse before half time.

SHOT! A rare sight of goal for the visitors as McGeehan plays the ball out wide for Donaldson, who finds himself in space over on the right channel. He drags his shot a little, though, and it bobbles a few yards wide of the far post.

CHANCE! For a player of Rooney's quality, this goes down as a chance. United break quickly with Di Maria leading the charge down the left, and he floats an inch-perfect ball across for Rooney, who must be licking his lips as it arrives to him on the volley. However, he doesn't catch it right and sends his effort harmlessly wide.

The fourth official indicates a minimum of two minutes added time at the end of this first half.

Jonathan Moss brings an end to the first and, and it is so far so good for Manchester United as they take a two-goal lead into the break. It has been a professional job for the hosts so far, and Cambridge have barely got a look in since squandered a glorious chance in the opening minute.

The first goal of the night came through Juan Mata, who tapped home from close range after Fellaini had won a header at the back post. The Belgian knocked Di Maria's cross down the Spaniard, who had a simple finish to break the deadlock.

Marcos Rojo then got his first goal for the club shortly after the half-hour mark to put the hosts in complete control. His was also a close-range finish, with Van Persie clipping a cross in to the Argentine, who glanced his header past Dunn. Fellaini had seen a shot blocked seconds earlier having been left completely unmarked from a corner.

It could have all been very different had Cambridge broken the deadlock within the opening minute of the game. Blind gave the ball away carelessly and Elliott found himself bearing clean through on goal with only De Gea to beat. He tried to curl a low effort into the bottom far corner, but was denied a dream start to the match as his effort came off the outside of the post.

In truth, it has been all Manchester United since that early scare, and it is hard to see them letting this slip now. The hosts have opted for a lot of crosses into the box in this match, with Fellaini playing in an advanced role in order to get on the end of them. It isn't necessarily a tactic we expect to see from United, but it has been effective so far, with both goals coming via crosses.

UPDATE: There have been equalisers in both of the other FA Cup replays taking place tonight. Sunderland have levelled things up against Fulham at Craven Cottage courtesy of a Marcus Bettinelli own goal, while Paul Gallagher has also made it 1-1 for Preston against Sheffield United at Bramall Lane. Remember, the winner of that latter tie will face either Manchester United or Cambridge United in the fifth round. Fulham and Sunderland, meanwhile, are bidding for a meeting with giant-killers Bradford.

Richard Money has a bit of a dilemma in the second half now. On the one hand, they have very little to lose by really going for it after the break, and they won't be in this situation often. However, he won't want his side to be on the end of a drubbing, and the gulf in class between the two sides was clear at times in that first half.

KICKOFF: Cambridge get us back underway as they look to pull off the most unlikely of comebacks in the next 45 minutes.

UPDATE: Speaking of comebacks, Preston have launched one of their own at Bramall Lane! They now lead Sheffield United 2-1 and are on course for a fifth-round meeting with Manchester United as things stand.

CHANCE! Cambridge have made a fairly bright start to the half, but they allow the hosts to break far too quickly here. Rooney comes forward before sliding a pass to McNair, who stands a cross into the middle. Van Persie gets his head onto it, but puts his effort wide.

CAMBRIDGE SUB: The first change of the match sees Luke Chadwick depart for Gearoid Morrissey, who makes his debut. Chadwick gets a good reception from both sets of fans.

CHANCE! Big chance for Van Persie to make it 3-0, but he is thwarted by Dunn. He collects the ball inside the box but can't squeeze it home from close range with the angle against him.

Another sight of goal for Van Persie, but once again his radar is a little off. This time it is a harder chance as he loses his marker from a corner but doesn't get anywhere near enough on his header to divert it goalwards.

CHANCE! Yet another huge chance for Van Persie! The ball comes out to Rooney, who fires a dipping volley towards goal from 20 yards. Dunn makes a bit of a meal out of it, spilling it at the feet of Van Persie, who can't squeeze the rebound home.

SAVE! De Gea has a very rare piece of action, but it is as routine as it comes for the keeper. Simpson attacks the near post to reach a cross, but his glancing header is straight at the keeper.

UPDATE: Cambridge don't exactly look likely to recover here, but comebacks are the order of the day elsewhere in the cup. Preston are now 3-1 up against Sheffield United courtesy of a Paul Gallagher penalty, his second of the night, while Sunderland have come from behind to lead Fulham through Ricardo Alvarez.

Di Maria looks to whip a corner into the middle and it very nearly flies straight in. There was plenty of venom behind the delivery, but Dunn keeps it out. Moments later Di Maria pops up in the box himself and curls an effort towards goal that Coulson nods away right in front of the keeper. That was an important block from the long-serving defender.

CAMBRIDGE SUB: Another change for the visitors as Simpson makes way to be replaced by Sullay Kaikai.

Better from Cambridge as they forge a rare attack, with Tait travelling with the ball down the right. Smalling is there to put the eventual cross behind for a corner.

CHANCE! Yet another sight of goal from Van Persie, but this time he plays a large part in creating the chance. Di Maria floated a ball over the top for Van Persie, who chests the ball down before hitting the volley on the turn and drawing a smart low stop from Dunn.

SHOT! A rare shot for Cambridge as Elliott does well to keep a long ball forward alive. Morrissey picks up the second ball and beats one man before dragging his shot wide from outside the box.

MANCHESTER UNITED SUB: Van Persie has had plenty of chances to score tonight, but he won't get another. The Dutchman is taken off to be replaced by James Wilson. Van Persie goes straight down the tunnel.

Another speculative effort from Cambridge as Kaikai beats one man in midfield before letting fly from a good 30 yards. His shot is high and wide of the target, though.

SAVE! United work the ball nice across from the right flank over to Di Maria just outside the box. He lines up a shot and sends a swerving effort towards the top corner that Dunn does well to palm over.

Elliott looks to be clean through on goal for the second time tonight, but this time he is wrongly denied by the linesman's flag.

MANCHESTER UNITED SUB: Di Maria's evening is over as Van Gaal looks to rest some of his key players in the last 20 minutes. The Argentine is replaced by Ander Herrera.

UPDATE: Sunderland have secured their place in the fifth round of the FA Cup courtesy of a third goal in stoppage time to lead Fulham 3-1 at Craven Cottage. Jordi Gomez got the strike, which sets the Black Cats up for a clash against Bradford City.

United have their third of the evening as two subs link up. Herrera pounces on a loose pass in midfield before giving the ball to Wilson, who works a yard before drilling a low effort into the bottom corner. Dunn probably should have done better with that one.

Well, if this one wasn't over beforehand, it certainly is now. United's pressure has been almost incessant since that opening chance for Cambridge and they have never looked in any danger of getting anything other than a comfortable win tonight. It has been a job well done by the hosts tonight.

A couple of sights of goal for United as first McNair gets forward to drive an effort over the bar before the full-back puts a decent cross into the middle. Rooney comes to meet it but can't make a proper connection as the ball rolls through to safety.

UPDATE: Confirmation of the full-time whistles in the other two FA Cup ties, with Sunderland and Preston both coming from behind to win 3-1 against Fulham and Sheffield United respectively. That means that Manchester United - barring a miraculous comeback from Cambridge here - will face Preston in the fifth round.

CLOSE! Rooney is eager to get his name amongst the scorers, and he almost does it here. He picks the ball up on the left and ducks inside before curling an effort towards the far corner. He can't get it back in enough, however, as it flies a couple of yards past the post.

MANCHESTER UNITED SUB: A third and final change for the hosts as Rojo, who got United's second goal tonight, is replaced by Ashley Young.

You get the sense that both sides would be happy if the final whistle were to blow now. Some Cambridge players may never want the Old Trafford experience to end, but they are looking increasingly tired out there having had to work very hard tonight.

United are simply playing keep-ball now, knocking it about inside the Cambridge half without any real urgency to break through the defence.

SAVE! Rooney ends United's long passage of possession with another curling effort from range, but this time it is comfortable for Dunn to save.

CAMBRIDGE SUB: A final change for Cambridge as Ian Miller comes on for the final few minutes, replacing Nelson.

Credit to the Cambridge fans, they haven't stopped singing tonight. Their team has been simply outclassed here, but in truth many of them wouldn't have been expecting anything different. No fewer than 6,600 of them have made the trip up to Manchester, and they are determined to enjoy the occasion.

There will be three minutes of added time at the end of this stroll in the park for Manchester United.

CHANCE! Almost something to cheer for the visitors late on! Elliott squeezes his pass through to McGeehan, who spins and finds himself with no defenders between himself and the goal. He shoots from the edge of the box but slices his effort a little and it goes wide of the near post.

There goes the final whistle, and it is a safe passage through to the fifth round for Manchester United. Cambridge had a great early chance inside the first minute but, from that point on, there never seemed to be any chance of an upset here tonight. Goals from Mata, Rojo and Wilson did it for the hosts, who will face Preston in the next round.

Right, that is all we have time for this evening! Thank you very much for joining Sports Mole for what proved to be a routine victory for Manchester United as they beat Cambridge to make it into the fifth round of the FA Cup. I will leave you with our match report, and be sure to stick around for reaction from both camps. The last FA Cup replay takes place tomorrow night as Liverpool face Bolton Wanderers at the Macron Stadium, and you can find live coverage of that match with us from 7pm. For now, though, it is goodbye from me!