Mourinho returns to Stamford Bridge for the second time this season as Manchester United travel to London to take on Chelsea in a crucial FA Cup quarter-final clash.
The newly crowned EFL Cup champions have several injury concerns and will miss one of their most important players this season Zlatan Ibrahimovic due to suspension.
Manchester United will take the field without a single striker in their Arsenal. Wayne Rooney received a knock during a training session clash with fellow teammate Phil Jones.
Youngsters Anthony Martial and Marcus Rashford too have been virtually ruled out of the clash due to illness.
In such a situation, Mourinho is somewhat right in treating the FA Cup clash with less importance.
Speaking ahead of the game, the Portuguese manager said: "For me, it's just a game that comes in the wrong moment for us.
"Because the Europa League is a competition that can give us a Champions League spot, and the FA Cup, it isn't. So the Europa League is more important than the FA Cup for us."
Manchester United have lost only a single game in the last 28 matches in all competitions but unfortunately, they are still placed in the sixth position in the EPL table.
Keeping in mind the level of competition in the Premier League, prioritising the Europa League seems to be a safe bet for Mourinho as winning it will directly place them in the UEFA Champions League next season.
The gaffer added: "The boys are doing really well, but we have opponents in different circumstances to us.
"Arsenal now are out of the Champion League, Chelsea without playing European competition, Liverpool not playing in European competition and we are in this run.
"We have Rostov on Thursday, then we have Middlesbrough on the Sunday at 12:15. It's very difficult for the boys, but these are the boys. Even in a match where it is impossible to play, we don't play, we fight."