United seem on course for the Wembley showpiece as they head into the second leg of their semi-final at Hull tonight with a 2-0 lead.
Reaching the February 26 final, however, would mean the Premier League game against neighbours and top-four rivals Manchester City, scheduled for the same day, having to be rearranged.
With both Manchester clubs still in the FA Cup and also due to resume European campaigns in the spring, it is unclear when that fixture could be played.
Mourinho said: “I know that it’s going to be hard if we go step by step. If, if, if - we go to the field of the ifs - but if we beat Hull and we play the final then we don’t play against Manchester City.
“The match against City I’m sure they will choose an amazing moment, difficult for us, to make us play against them. Then we have Europa League, a non-stop competition. In the Europa League you have to play last 32 and last 16. If we are going to progress it’s going to be really difficult. Let’s see what happens in this moment. In this moment we have a 25 per cent chance to win the League Cup, which is the first competition to be decided.”
Hull appear to have been given a new lease of life by the appointment of Marco Silva as manager a week before the sides met in the first leg at Old Trafford. The Tigers remain deep in relegation trouble but Mourinho believes his fellow Portuguese will give them a fighting chance.
He said: “I knew it, (it is) no surprise for me. It was not just the immediate impact of any team that changes the manager. For the next couple of weeks there is always an impact, a new feeling, but then things normally go back to the previous situation.
“I knew that Marco is such a good coach that the team would really improve. It is still a difficult job in hand, still a big fight with six or seven teams for relegation, but he is a very good coach.”
Mourinho has strong history with the League Cup having won it three times across his two spells in charge at Chelsea, but he does not believe success necessarily has wider significance.
“I don’t see things in this perspective,” he said. “It’s nice to win competitions but I don’t think it’s crucial to doing well after that.”
Mourinho was speaking at a press conference to preview the match sporting a new, closely-cropped, hairstyle.
“The haircut is a privilege,” he said. “It is a privilege because I’m the kind of guy that can do it and in one month have a new wig! Some of you can’t do it!” Mourinho did not wish to comment on recent remarks from Alex Ferguson he “has done a great job” but he did say the former United boss had provided valuablesupport from a respectful distance.
He said: “He doesn’t want to be around and come too many times. I told him this is his house always and forever, but just a couple of times. He travelled with us in the bus and the train, he visited us once, but we know this is his club, his life, and that he is supporting us.”
For his part, Hull coach Silva agrees Ryan Mason’s head injury has put a different perspective on his challenge to keep the club in the Premier League. Midfielder Mason is currently making “excellent progress” in St Mary’s Hospital in London after surgery on Sunday to repair his fractured skull, sustained during Hull’s defeat at Chelsea earlier in the day.
Silva said the club’s main priority was to maintain its support of Mason and his family as the England international recovers from the damage caused by his clash of heads with Chelsea defender Gary Cahill.
“At this moment we need to forget everything,” Silva said. “The most important is the player and his family, the other things are not important.”