United stepped up after a lacklustre start to beat Championship Wigan 4-0 at Old Trafford on Sunday with goals from Marouane Fellaini, Chris Smalling, Henrikh Mkhitaryan and the returning Bastian Schweinsteiger.

Mourinho was pleased with the result but fears there could be a price to pay as United's schedule gets even more congested.

United are already through to the EFL Cup final, which means a Premier League derby clash against Manchester City needs to be rearranged, while their Europa League campaign also resumes next month.

Mourinho said: "We are going to have a very difficult season compared with other clubs. Liverpool will play 16 matches until the end of the season, Chelsea will play 16 plus some in the FA Cup and we are in this really crazy situation.

"Southampton will have 15 days without football before the final. In those 15 days we are going to play two matches against Saint-Etienne and the next round of the FA Cup, so the calendar in the best country of world football is nonsense."