The eagerly anticipated clash between two of England's big clubs takes place tonight in what is expected to be a thrilling game, with the winner expected to be the favourites to lift the FA Cup this year. Liverpool are also in the mix but they must overcome Blackburn Rovers in a replay after yesterday's (Sunday) 0-0 draw at Anfield. With many players injured or having mediocre seasons it has been very difficult to pick a strong eleven from these two sides, who do have a lot of talent in their ranks. Because of this, many big names have missed out with a couple of surprise inclusions filling in.
Formation (4-2-3-1)
Goalkeeper: David de Gea (Manchester United) - The obvious choice in between the sticks is the Spaniard who has been United's best player this season. He faces no competition from the Arsenal keepers in David Ospina and Wojciech Szczęsny who aren't even among the best in the Premier League.
Right back: Héctor Bellerin (Arsenal) The 19-year-old has had a very good season at The Emirates and his frightening pace has proved to be very useful in both attack and defence. He has been given regular Football in the absence of Mathieu Debuchy and he just about edges out Antonio Valencia in this team.
Centre back: Laurent Koscielny (Arsenal) - He is highly regarded in the French set-up and is Arsenal's best defender.
With Manchester United struggling to find their best centre back partnerships, he fits in with ease.
Centre back: Marcos Rojo (Manchester United) - The Argentine, who is also a capable left back, makes the team as he has been United's number one defender this season. He has settled in well and has always been strong whoever he plays alongside.
Left back: Ashley Young (Manchester United) - A surprise inclusion in this position but he has regularly featured for United in the wing back position. He has been one of their better players under Louis Van Gaal and is sure to feature tonight. He beats Luke Shaw to the position as the youngster hasn't lived up to his £27 million price tag so far.
Central midfield: Daley Blind (Manchester United) - He was drafted in to protect the back four and he has been very good this campaign in playing his role. The Dutchman who played as a left back in the World Cup is a neat and tidy player who rarely gives possession away and he keeps things ticking over with his quick passing.
Central midfield: Francis Coquelin (Arsenal) - The young Frenchman has had an excellent season for the Gunners after coming back from his loan spell at Charlton Athletic. His statistics are up there with the very best in the league and it's no surprise that Arsene Wenger's men have improved since he has been a regular in the first eleven.
Right midfield: Santi Cazorla (Arsenal) - He has had one of his best seasons at Arsenal, scoring seven league goals in his 27 appearances in the league.
He has scored some crucial goals for them and has fit in nicely in a deeper role at times as well.
Left midfield: Alexis Sánchez (Arsenal) - He has had a brilliant first season in London and has been the Gunners best player so far. His performances have dropped off in recent games but 13 goals and 7 assists in the Premier League is outstanding and his team would be a lot worse off without him.
Attacking midfield: Wayne Rooney (Manchester United) - He has often been played in a deeper role this season but every game he plays has been beneficial to his team. Has led by example with many new faces coming in and is still regarded as their best striker at the moment even with Radamel Falcao and Robin van Persie in the team.
Striker: Olivier Giroud (Arsenal) - Has come back in the team after his broken leg and has been fantastic. Despite Danny Welbeck impressing, the French striker has regained his place and is scoring goals regularly. He is a natural goal scorer with a lot of qualities you want in a lone striker and he's led the line very well.
