United are still aiming for a top-four Premier League spot, while winning the Europa League would also secure a spot in next year's Champions League.

Mourinho conceded that United's focus will be on those two competitions as the FA Cup only provides a Europa League spot -- already secured by United's League Cup win -- but that doesn't mean he plans to rely on Nicky Butt's reserve team against Chelsea.

"We want to keep the two doors open," he said of United's route to the Champions League after their 1-1 draw at Rostov in the Europa League on Thursday.

"We have to keep getting points in the Premier League to let us go to the last months of the competition with that door open.

"In the Europa League, if we manage to go through this knockout round, we go to the quarterfinal and then you feel that the door is open.

"So we have to try, we have to try by every means. We have a trophy in our pocket, which is always a good thing, a good feeling for everyone.

Man United have to turn around from their trip to Rostov to face Chelsea on Monday.

"But now we have the Premier League top-four to fight for, the Europa League to try and beat Rostov, and Monday we don't go with a Nicky Butt team.

"We cannot go with Nicky Butt's team. Manchester United is too big. Manchester United is the winner of the competition.

"It is not Chelsea's fault that we were given this Monday match, so we have to make changes for sure because we play Thursday against Rostov and they play Sunday against Terek Grozny.

"But we cannot go to Stamford Bridge with a Nicky Butt team."