Claude Puel's team are not to be underestimated, though, despite their league position, seen as though they haven't conceded a single goal in their route to the final and have knocked out both Arsenal in the quarters and last season's runners-up Liverpool in the semis.
Victory for Jose Mourinho would result in him being the first manager in the famous club's history to win a trophy in their first season (excluding Community Shields) so he'll definitely be going for it and his team selection will justify that.
Goalkeeper - David De Gea: United's back-up goalkeeper Sergio Romero has started the last three matches, all cup fixtures, but it's likely that David De Gea will return between the sticks in such a big game. Romero has been touted as 'the best second goalkeeper in the world' and his statistics back that title up perfectly considering he's kept seven clean sheets in his nine appearances this season while conceding just twice. This game is being slightly downplayed simply because of the competition however the truth is that it's silently a huge game and Mourinho will want to field the strongest team possible.
Right-back - Antonio Valencia: Like the Spanish keeper, Antonio Valencia has made way for another player in need of minutes in recent games as Ashley Young started the FA Cup win at Blackburn Rovers and the Europa League second leg victory against Saint-Etienne. It's obvious that Valencia is Mourinho's first choice right-back because of his ability in the wing-back role and the team will be full of first-choice players so it wouldn't be surprising if the Ecuadorian is recalled.
Centre-back - Chris Smalling: Phil Jones isn't expected to be ready in time for the match and even if he was fit it's unlikely that he'd start so that leaves a choice of Chris Smalling, Eric Bailly and Marcos Rojo. However, Jose Mourinho has expressed how pleased he has been with how the back four featuring Smalling and Bailly in it has looked so it's doubtful that he'll make drastic changes now. With United gathering momentum it seems like the Englishman is gaining the confidence back that made him one of the best defenders in the league last term.
Centre-back - Eric Bailly: Eric Bailly received the first red card of his Manchester United career during midweek in Saint-Etienne and will miss the next European fixture away at FC Rostov but he's available tomorrow so Mourinho will want him in the back four he considers at his strongest at the moment. Bailly has impressed in his debut season in England so he'll be keen to win his first major trophy just seven months in.
Left-back - Daley Blind: With Luke Shaw currently out of the picture, the left-back position is currently being contested by Daley Blind, Marcos Rojo and Matteo Darmian but Blind has been part of Mourinho's favoured back four recently and its likely he'll be there again at Wembley. The versatile Dutchman is sometimes caught out because of his pace and Rojo might be picked in order to deal with Southampton's pacy wingers Boufal and Redmond but why change something that's working so well?
Defensive-midfielder - Michael Carrick: Jose Mourinho confirmed in his press conference that Michael Carrick was fit to feature in the final tomorrow so with Henrikh Mkhitaryan missing it seems certain that United will play in a 4-3-3 rather than a 4-2-3-1. Carrick sitting just behind Pogba and Herrera has worked wonders this season so it only seems right to start off the game with the same combination. With Wayne Rooney expected to take a place on the bench, the 35-year-old midfielder looks set to be the man leading the team out onto the Wembley turf for potentially the last time in a cup final.
Centre-midfielder - Ander Herrera: The Spanish fan favourite missed the trip to Saint-Etienne on Wednesday night due to suspension but has been utilised in nearly every one of Mourinho's games this season so it's clear that the Portuguese manager likes him. He's been in great form alongside Paul Pogba in midfield and some are even touting him as a future captain so his passionate style of play will prove vital tomorrow.
Centre-midfielder - Paul Pogba: These are the types of games that players like Paul Pogba cherish and look forward to, he returned to Manchester United to win trophies and can make the perfect start to his career in England tomorrow afternoon. With the label of being the world's most expensive player lingering around him, there's no doubt that fans all over the world will be expecting him to step up and make a big difference in such a big game and he'll be eager to do exactly that.
Right-winger - Marcus Rashford: Juan Mata is odds on to start in the place of the injured Henrikh Mkhitaryan because of the overall quality he brings to the team, however, strong reports were coming out today that Mata hasn't actually travelled to London with the squad. It's another big blow and means the attack is weakened a bit more but it's known that Jose Mourinho has great faith in Rashford and tomorrow's fixture presents a perfect chance for the young star to repay his manager's faith in him.
Left-winger - Anthony Martial: When Anthony Martial was struggling to even get on the bench for United a few weeks ago rumours were flying all over the place about his future, but since returning to the team he has looked like the brilliant talent of last season. His omission from the first team picture was a stroke of managerial genius from Jose Mourinho and the Frenchman has now been involved in 17 goals from 17 appearances this season, not bad for a 'one season wonder'.
Striker - Zlatan Ibrahimovic: The fight for a place in this position just isn't even a contest at the moment with the form that Zlatan Ibrahimovic is in. The Swedish forward arrived onto the scene in typical Zlatan fashion in August, scoring the winner at Wembley Stadium on his competitive debut when United were victorious against Leicester City in the Community Shield final and he'll want to make the same impact at Wembley again.