Jose Mourinho has made clear he would rather win the Europa League than finish in fourth place in the Premier League.
United are in the running to take out the Europa League crown and are due to face Belgian side RSC Anderlecht in the quarter-finals.
Winning the tournament grants qualification immediately into the Champions League.
The Red Devils are fifth in the Premier League, and their win over Middlesbrough to them to within four points of fourth-placed Liverpool.
Speaking after the game, Mourinho said his sights were set on winning the continental competition.
“If we don’t win this match today, we lose the chance in relation to Arsenal’s defeat, we lose the chance in relation to Man City vs Liverpool … somebody is going to lose points (it ended in a 1-1 draw),” Mourinho said.
“So it was very important to keep us alive.
“Do I prefer to finish fourth or win the Europa League? I prefer to win the Europa League because Europa League gives us the same, it gives us Champions League football, but it gives us a trophy.
“But maybe we don’t win the Europa League, so we have to fight until we can to try to finish fourth and that was what we did today without many players.
“But we had a great answer in terms of attitude and desire from all the boys, so it’s a massive, massive victory for us.”
Goals from Marouane Fellaini, Jesse Lingard and Antonio Valencia were enough for United to claim the win.