Where to watch live
Kick-off is set for 4:30pm GMT. Live coverage of the game will be on Sky Sports 1 and Sky Sports 1 HD.
The Red Devils will be without their attacking midfielder Henrikh Mkhitaryan, who suffered a hamstring injury during Wednesday's 1-0 Europa League win at Saint-Etienne. Michael Carrick should be fit to start despite the midfielder coming away with a calf injury in France, while Phil Jones has been struggling with a foot problem.
This will be United's ninth League Cup final appearance where they have won four and lost four, but have won their last three finals in the competition. Should they win, this will be their second major trophy in back to back years after winning the FA Cup under Louis van Gaal. Mourinho has reached the League Cup final three times previously and has won the trophy each time. The Portuguese manager has never lost a domestic cup final in his career and has the best win percentage in the final of the League Cup.
This is the second time that Southampton are facing United in a domestic Cup final, having played each other in the 1976 FA Cup final. The Saints, then from a lower division, defeated United 1-0 thanks to a Bobby Stokes goal. It was also the only time they won a major trophy.
Southampton have reached the final of the League Cup without conceding a single goal, and are only the second side in League Cup history to achieve that feat after Tottenham Hotspur's achievement in 1981-82.
The Saints have a host of injury problems, with Charlie Austin, Virgil van Dijk, Jeremy Pied, Matt Targett and Alex McCarthy all ruled out. However, playmaker Sofiane Boufal is likely to return from an ankle injury.
What Managers Say
Jose Mourinho: "If Southampton want it more than us on Sunday then they will win the match. So we have to make sure that they do not want it more than us. Of course they want it a lot. But I do not think that they want it more than us. I think the best team on the pitch will win and it will not depend on motivations. It's a much important trophy. I think it's always good to win. It doesn't matter what comes next, it doesn't matter the impact. I don't believe it will have an impact. I think when you have a taste of good things, you want to repeat. When you are used to winning and you don't win, you miss it and you don't accept it. You are always chasing for more success so it's a good thing for them. We all know the history of this club. We all know football is changing. We all know that it is much difficult than it was before."
Claude Puel: "I don't know if it's a benefit because two weeks without an official game is sometimes difficult. At the beginning, it's interesting to give a day off for the first time since the beginning of the season for the team. After, it's always difficult to prepare and to find a good balance and do good work to keep a good rhythm without games. It's a good challenge. We will see, of course, on Sunday but sometimes I prefer to play every two or three days. Sometimes, with an official game every three days, it is better."
Betting Odds (betfair)
- Manchester United win: 3/4
- Draw: 11/4
- Southampton win: 9/2
Possible XI: De Gea; Valencia, Smalling, Rojo, Blind; Herrera, Pogba; Lingard, Mata, Martial; Ibrahimovic
Possible XI: Forster; Soares, Stephens, Yoshida, Bertrand; Davis, Romeo; Ward-Prowse, Tadic, Redmond; Gabbiadini