Arsenal boss Arsene Wenger faces arch-rival Jose Mourinho for the last time as Gunners boss on Sunday, although the Frenchman will most likely have one eye on next week's crucial European semi-final clash against Atletico Madrid.
Wenger and Mourinho have had fierce battles on the touchline over the years, with the latter previously labelling the Arsenal manager a "specialist in failure", while Wenger once said: "When you give success to stupid people, it sometimes makes them more stupid."
The Gunners top four hopes are out of sight and with the Europa League hanging by a thread, it's expected that Wenger will ring the changes for Sunday's historically intense clash.
Former Arsenal forward Alexis Sanchez will also feature against his old club for the first time since leaving the north Londoners in January.
Henrikh Mkhitaryan is running again in training but won't be fit for Sunday's game, with Wenger targeting the match in Madrid as a potential return date for the Armenian.
Egypt midfielder Mohamed Elneny is out with ankle ligament damage and is expected to be on the sidelines for at least a fortnight.
Spanish midfielder Santi Cazorla remains a long-term absentee with an Achilles injury, although he was pictured training on the Emirates pitch before the Europa League semi-final against Atletico on Thursday.
Arsenal have no suspended players for this game.
Arsenal potential starting line-up
Wenger could rest a number of players ahead of Thursday's crucial Europa League semi-final second leg against Atletico Madrid.
The likes of Alex Iwobi and Sead Kolasinac could start, while Ainsley Maitland-Niles, Calum Chambers or Rob Holding are able to fill in for Laurent Koscielny, with the Frenchman carefully managing his chronic Achilles problem.
Pierre-Emerick Aubameyang is expected to return up front and could play alongside Welbeck, with Petr Cech expected to return between the sticks.
Manchester United team news
Mourinho could look to field an unchanged side in the familiar 4-3-3 formation with Alexis Sanchez likely to start against his former club alongside Romelu Lukaku and Jesse Lingard.
United are without Sergio Romero who has a knee injury while Antonio Valencia is expected to be fit, despite hobbling off with a muscle problem during the FA Cup semi-final win over Spurs at Wembley.
Lukaku is the club's top scorer with 26 goals to his name so far this season.
Best Opta match facts
Manchester United are unbeaten in 10 home league matches against Arsenal (W7 D3), their longest run since March 1961 (17 games).
In all competitions, Arsenal have lost 13 of their last 18 away visits to Old Trafford (W2 D3), although only one of those defeats has been in the last four visits (W1 D2).
The Red Devils haven’t completed a league double over the Gunners since the 2011-12 campaign – the last Man Utd manager other than Sir Alex Ferguson to achieve this was Ron Atkinson in the 1984-85 campaign.
This will be the 19th meeting between Jose Mourinho and Arsene Wenger in all competitions - Mourinho didn’t lose any of the first 13 (W6 D7) but has lost two of the last five (W2 D1). However, he’s never lost at home against Wenger in seven matches (W4 D3).
Alexis Sanchez could become the first player to score both for and against the same team in the same Premier League season since Wilfried Bony in 2014-15 (who scored for and against both Swansea and Man City).
Danny Welbeck has scored on both of his visits to Old Trafford for Arsenal in all competitions – no Arsenal player has scored away at Man Utd more under Arsene Wenger (Emmanuel Adebayor and Sylvain Wiltord also two).
After a run of just one goal in 11 Premier League games, Alexandre Lacazette has now scored four in his last four, including a brace last time out vs West Ham.
TV channel & kick-off time
The match kicks off at 16:30 BST on Sunday with live television coverage available on Sky Sports in the UK.