Mourinho, who takes his side to Anderlecht for the first leg of their Europa League quarterfinal on Thursday, had said United could switch their focus from the Premier League to their European campaign if they were to lose sight of a top-four finish this week and then saw his side held by Everton.

United, though, reduced the gap to fourth-placed Manchester City to four points, with a game in hand on their rivals, after a 3-0 victory at 10-man Sunderland -- a result that pushed David Moyes' side to the brink of relegation from the Premier League.

Mourinho said: "After Liverpool and Manchester City's victories, if we didn't win today it's almost mathematically impossible [to finish fourth]. It was important for us to win and that was the main objective.

"We did that and, apart from that, there were no more injuries to add to the difficult list we have, because we don't hide that we are still fighting for our situation in the Premier League.

"But the Europa League becomes fundamental for us, it's the only competition we can win now. We did the Community Shield, we did the League Cup. The Premier League, no way, so it is our competition to fight for.''

Victory on Wearside was secured by Zlatan Ibrahimovic's 30th-minute strike and, after Sebastian Larsson had been controversially dismissed by referee Craig Pawson for a challenge on Ander Herrera, second-half goals from Henrikh Mkhitaryan and substitute Marcus Rashford.

Jose Mourinho takes Manchester United to Anderlecht for the first leg of their Europa League quarterfinal on Thursday.

But it was full-back Luke Shaw, criticised roundly by Mourinho in recent weeks, who earned a pat on the back from the manager following a composed display. He was taken off just after the hour-mark following an early caution.

Mourinho said: "He played well, played solid. The opposition was not creating big problems, but he was solid and was confident with the ball. He was going forward with some danger, he was reading the game well to go when Mkhitaryan went inside. He played really well, so it was a good hour for him.

"I thought about a half-time change, but thought it was too harsh for him. I wanted him to play a little bit more, so at 2-0, one hour in, with the crowd asking for everything and putting the referee under a little bit of pressure, no risk [taken]. We have no players, we need him to be available for the next match.''

Mourinho left David De Gea out of the squad for the Sunderland game but said he was confident he would be fit in time for next Sunday's meeting with Chelsea, with Sergio Romero set to continue in goal against Anderlecht.

"He has a problem with his hip," Mourinho told BBC Sport. "When he dives he feels it a little bit. It's good for him to have a rest. It's good for Sergio Romero to play before Brussels. De Gea will probably be fit for Chelsea -- yes, if he's in good condition."

It proved to be another bleak afternoon for former United boss Moyes, whose Sunderland side remain 10 points adrift of safety with just seven games remaining.

Sunderland will consider an appeal against Larsson's dismissal with Moyes convinced his midfielder was harshly treated.

Moyes said: "We'll have a look at it. I've had a look at it, so don't worry about that, I've had a look at it. I don't want to make you think it's the referee's fault, it's not that. But he gets the ball, he touches the ball. There's no contact at all, so it's not even a booking.

"What I don't want to do is in any way blame the referees because our position is where we are, we are bottom of the league, so let me make that clear first of all, it's nothing to do with referees. But I didn't think it was a good decision.''

While Sunderland are in real trouble of being relegated, Moyes is refusing to admit defeat.

Asked about their situation, he said: "It's still as difficult -- probably more difficult because there's a game less. The game less means it's tougher. There's no hiding the fact that we're in a difficult position. But we've got a home game next, let's see if we can get some momentum, try to get a win in that and we'll try to do that.''