Darren Fletcher joins Alan Shearer, Phil Neville, Jimmy Floyd Hasselbaink and Gary Lineker at Stamford Bridge on Monday for live coverage of Chelsea v Manchester United in the FA Cup on BBC One and the BBC Sport website from 19:00 GMT. Manchester United manager Ole Gunnar Solskjaer's tactical flexibility has already seen his side win at Tottenham and Arsenal in the past month and it could be the key to them beating Chelsea on Monday too. United will be without Jesse Lingard and Anthony Martial for their fifth-round FA Cup tie because of injury, but Solskjaer will still have plenty of options over how he sets his team up, and crucially he will be able to change things during the game too. That flexibility is the biggest difference between United and Chelsea at the moment, because we know what we are going to get from Maurizio Sarri's side. The Blues boss is not going to move away from his 4-3-3 formation, and his players are very restricted in terms of alternating positions and where they operate on the pitch. That can be a strength as players know the system so well, but at the moment being so rigid is also a weakness, especially in a scenario like this one. Chelsea have suffered some hefty defeats in recent weeks, including a 4-0 loss at Bournemouth on 30 January. Sarri has changed his personnel in midfield and attack since then - with Pedro and Ross Barkley coming in for Willian and Kovacic for the 6-0 defeat at Manchester City on 10 February for example - but his formation has stayed the same It means playing Chelsea is an easier game to prepare for, because there are not going to be any surprises. United can look at their previous matches to identify any weaknesses and come up with a game plan. But if that plan doesn't work for them, in an instant United can adjust their shape - and their players are adaptable enough to do that constantly if they have to. In my time at United, Stamford Bridge was a notoriously hard place to go. They have only won twice there since 2002 and have lost 14 out of their past 22 visits. But despite that poor record, I think Solskjaer will look at this game and think there are opportunities to exploit in the same way United did at Wembley and Emirates Stadium. Pogba can cause Jorginho problems Against Spurs and Arsenal, United essentially played with a midfield diamond and two forwards in wide areas. It worked very well. I would not be surprised if Solskjaer did that again and used Marcus Rashford and Romelu Lukaku or Alexis Sanchez in those roles up front. Behind them is where Solskjaer has got the flexibility I am talking about. Man Utd not on PSG's level - Ole Gunnar Solskjaer With Paul Pogba, Ander Herrera and Nemanja Matic in the team, he has the choice of a single or double pivot at every stage of the game. If they decide to match up with Chelsea and go with a 4-3-3, that could see Matic sitting with Herrera and Pogba either side of him, but they could easily switch to have Matic and Herrera protecting the back four together, with Pogba pushed forward as the number 10. United played a 4-3-3 against PSG on Tuesday, with Martial and Lingard in wide roles. Lukaku, Sanchez and Rashford could make up the front-line against Chelsea if Solskjaer matches up against the Blues' formation and goes with Pogba, Matic and Herrera across his midfield In contrast, 'Sarri-ball' will see Chelsea play with a single pivot in their 4-3-3, with Jorginho as that deep midfielder, with N'Golo Kante and probably Mateo Kovacic either side. If you look at the physicality of all of those players, United's midfielders are a lot bigger and more powerful, which is another reason I think this is an area in which they will be able to impose themselves on the game. Personally, I would put Pogba directly up against Jorginho - firstly to stop him, because if you give the Italy midfielder time he dictates play and makes Chelsea tick, but also because of the damage the France midfielder could do when United win the ball back. Jorginho is not in that role to be a defensive midfielder - he is there as a playmaker. Pogba is much stronger than him and, in the form he is in, he will cause him all sorts of problems if they go to head-to-head when United attack. There is more than one way for Solskjaer to do that, though. If he goes with the diamond again, he could put Pogba at the tip of it and bring in another midfielder - say, Fred, to play on the left. That way, United would outnumber Chelsea four to three in midfield and still have Pogba sitting on Jorginho, who will be at the base of Chelsea's midfield no matter what. Rashford and Martial played in front of Lingard when United used a midfield diamond in their 1-0 win over Tottenham on 13 January, while Lukaku and Sanchez played in those roles, again with Lingard behind them, when they used the same shape to beat the Gunners 3-1 at Emirates Stadium in the FA Cup fourth round on 25 January. With Lingard currently injured, could Pogba take that role instead? Flexibility would suit Kante Paris St-Germain did a superb job on United's midfield last week, playing five in the middle with Marquinhos tracking Pogba to stifle him completely. Kante is the only Chelsea player who might try to do the same thing on Monday, but I can't see it happening. Even if he does follow Pogba, the former Juventus player can just drop on to Jorginho and if Kante is in the same area too that would leave a massive space elsewhere in Chelsea's midfield for someone else to exploit. When 'Sarri-ball' is questioned, it is usually his use of Kante in a more advanced role that is brought up, but we have to remember he is not and has never been used in the Makelele role while in the Premier League. In any case, Sarri wants something different from his holding midfielder. Jorginho is there to play the Andrea Pirlo role or, as it is known in Italy, the 'Regista'. He is not there to tackle and break play up, he is there as a deep-lying playmaker. Even if the Makelele role was what Sarri wanted, that is not what Kante has done in any of the other Premier League teams he has been in. I am sure he could do it, but when he was winning the title with Leicester and again under Antonio Conte at Chelsea, Kante was not the midfielder who sits in front of the back four on his own. Kante, 27, won the Premier League in his first season with Chelsea in 2016–17. He signed a new five-year contract with the club in November 2018 At Leicester, Danny Drinkwater went deeper to get the ball and Kante was the energy around him. It was the same when Kante first moved to Chelsea under Conte and Matic was still there. Again, he was the more mobile of the two and Matic was the sitter. One of the reasons Kante was so effective in those teams was actually because they had the same flexibility United do now. Sometimes he would find himself doing that sitting job because his position dove-tailed with what his team-mates were doing. Now it is different because Jorginho has to be in his set position all the time so Kante's role involves dragging people away. He has to wait for the next phase of the move to see the ball, and before that he has to play further forward to create space for Jorginho. That works when Chelsea are attacking but it does affect Kante's defensive contribution whenever a move breaks down. As we know, he is a fantastic athlete but from up the pitch he cannot recover the bigger distances that are left when they lose the ball, and that leaves Jorginho exposed. Herrera has a role to stop Hazard too For United, getting things right does not just mean finding the right combination in midfield that allows them to dominate Chelsea. They have to be set up properly from a defensive point of view too. Chelsea might be having a bad time of it recently but they still have some extremely good players, and they are very dangerous when they get it right. We know Eden Hazard is a match winner, whatever else is happening on the pitch, so it is vital United's plan takes him into consideration at all times. To do that, whatever United's formation is, I think Herrera has to play on the right side of midfield and he will have a dual role there. Man Utd's Ander Herrera and Alexis Sanchez talk about their love of football As well as being in midfield, part of his job will also be to double up with United's right-back Ashley Young against Hazard on that flank. Hazard loves to come inside on to his right foot, which is when he is most dangerous. Young will always try to show him down the line but you cannot leave your full-back one on one with Hazard because he is just too good - too sharp and too fast. He can still get where he wants to go with a drop of the shoulder, so Herrera will have to be there to plug that gap every time. Sarri needs time, like Pep did I want to play my football at Chelsea - Sarri Sarri is getting some stick at the moment because of Chelsea's recent results, but his methods were never going to see an instant impact. The easiest way to implement a different style of football and get results quickly is to adopt a defensive approach. Conte, who won the title in his first season at Chelsea, is a good example of that. He was not worried about dominating possession and he made his team hard to break down and played on the counter-attack. The harder way, as Sarri is finding at the moment, is when you are trying to keep the ball and be open and expansive. Not only do you have to be good defensively, you have to try to break the opposition down and it is a much longer process to get right. What is happening now at Chelsea is quite similar to what Pep Guardiola experienced in his first season as Manchester City boss in 2016-17. Until Sarri nails down exactly what every player does, and they get that transition from attack to defence sorted so they know what happens when they lose the ball, they are going to continue to look vulnerable. It might be that he does tweak the way he uses Kante and Jorginho because, like Pep, he realises some of the things that worked very well in a different league do not work the same way here. It took Pep time to get it right, and a couple of transfer windows too, but look at where City are now. If Chelsea believe in Sarri in the same way, which they must have done when they gave him the job, then they have to be patient too. Darren Fletcher was speaking to BBC Sport's Chris Bevan.<doc-sep>Last season, Chelsea and Manchester United met at Wembley in the final of the 2018 FA Cup. Chelsea won, thanks to a penalty that Eden Hazard drew and converted. He’s still here, as are many of the players, but a lot has changed regardless in those intervening nine months. Both teams are under new management, Chelsea persevering with Sarri, United going the Chelsea route and sacking Mourinho to enjoy a new coach bounce with former player Ole Gunnar Solksjaer. Chelsea are idealistic to a fault and possibly trending down, United are simply letting good players be good players and possibly trending up. Considerations of form, function, and facility often go out the window in Cup games however. Usually, it comes down simply to which team wants it more. The rest of the last 16 round has featured almost no upsets and no certainly no giant-killings. Can Chelsea stay strong at home at least, and join the seven other qualified teams (City, Wolves, Palace, Watford, Brighton, Millwall, Swansea) in the quarterfinals? Date / Time: Monday, February 18, 2019, 19:30 GMT; 2:30pm EST; 1am IST (next day) Venue: Stamford Bridge, SW6 Referee: Kevin Friend — third Chelsea match for Mr. NotMyFriend this season after the 0-0 draw against Everton and the 2-1 away win over Liverpool B in the League Cup. Forecast: Light rain On TV: BBC One (UK); none (USA); Sony ESPN? (India); elsewhere Streaming online: BBC iPlayer (UK); ESPN+ (USA); ESPN India Chelsea team news: Ruben Loftus-Cheek may or may not miss this game with the latest recurrence of his back problem, but otherwise Chelsea have basically a full squad available to pick from (minus the ostracized ones like Danny Drinkwater or Gary Cahill). Sandwiched between the two legs of the Malmö FF matchup in Europe and followed by the League Cup final next weekend, Sarri’s likely to field as strong of a lineup as he possibly can, as Chelsea look for back-to-back wins for the first time this calendar year. Manchester United team news: Chelsea-killers and scorers of the last three goals United had managed against us, Anthony Martial and Jesse Lingard are both out. They join long-term injury victims Antonio Valencia and Matteo Darmian. After winning 10 or 11 games under Solksjaer, United were rudely exposed by a willing PSG at Old Trafford last week. They will surely want to avoid dropping out of this cup as well. Previously: Last year’s final.<doc-sep>
PLAYER RATINGS: Scores of NINE for Manchester United after phenomenal 2-0 win against Chelsea in the FA Cup PLAYER RATINGS: Scores of NINE for Manchester United after phenomenal 2-0 win against Chelsea in the FA Cup by Ali Akbar Manchester United take on Chelsea tonight hoping to win for the first time in nine trips to Stamford Bridge. Ole Gunnar Solskjaer will be looking for a response from his player’s after the loss to PSG in the week, but who will he pick in his starting lineup? Ollie Slack Chris Smalling comes into the back four in my starting XI in the place of Eric Bailly. The Ivory Coast international was not particularly poor against the PSG, however, he was at fault for Kylian Mbappe’s goal, failing to cut out the cross from Angel Di Maria at the front post. Smalling’s presence against strong solo-centre-forwards has been very useful in the past. He always seems to perform better against a Harry Kane or Alexandra Mitrovic type player. Tonight’s match against Gonzalo Higuain will be another tricky test, though. No change in the midfielder three as always, although, Ole Gunnar Solskjaer will be hoping for a similar performance from Paul Pogba as the one he delivered against Arsenal in the previous round. The counter-attack Frenchman was at his absolute best that night. With Anthony Martial and Jesse Lingard injured, Alexis Sanchez and one other come into the starting lineup. I expect Tahith Chong to possibly come into the match later on. It was a tough call between Romelu Lukaku and Juan Mata, for the other starting spot. Two very different opponents but I thought both could add value to United’s attack against Chelsea. If the Blues are going to try and press Solskjaer’s men as they did against City last week, then you need a man who is strong in possession like Mata. However, with Marcos Alonso struggling in Maurizio Sarri’s system, evident on last week’s display at the Ethiad, I thought Romelu Lukaku might be able to steamroll the Spaniard tonight. David de Gea Ashley Young, Chris Smalling, Victor Lindelof, Luke Shaw Ander Herrera, Nemanja Matic, Paul Pogba Romelu Lukaku, Marcus Rashford, Alexis Sanchez Ali Akbar Lindelof and Bailly looked good for most of the game against PSG so this should be the starting centre-back partnership against Chelsea and beyond. Dalot’s accurate crossing would be a useful asset against Chelsea’s tall back four. However, he isn’t disciplined enough defensively, so Young should keep the right-back spot. This midfield three was poor against PSG, but Solskjaer should resist the temptation to switch things up. Herrera’s inclusion in the starting XI will be vital in particular – given his man-marking ability. Since Lingard and Martial are injured, Chong and Sanchez should play either side of Rashford, with Lukaku coming off the bench in the second half for either of them if necessary. David de Gea Ashley Young, Eric Bailly, Victor Lindelof, Luke Shaw Ander Herrera, Nemanja Matic, Paul Pogba Tahith Chong, Marcus Rashford, Alexis Sanchez