Bottom club Sunderland’s hopes of avoiding relegation suffered another setback as Manchester United eased to victory to climb to fifth in the table.
Sunderland played with 10 men for more than 45 minutes after Sebastian Larsson’s controversial red card for a challenge on Ander Herrera.
Zlatan Ibrahimovic had already put United ahead with a sublime, curling 20-yard effort.
Henrikh Mkhitaryan made it 2-0 before Marcus Rashford drilled in the third.
Sunderland are 10 points from safety with just seven games left and have not scored for seven matches.
United, who move above Arsenal, are four points behind fourth-placed Manchester City with one game in hand over their neighbours.
This was Sunderland’s 21st league defeat in 31 games this season, while they have now gone 11 hours and 15 minutes without scoring in the top flight.
It is hard to see where another win is going to come from and the Black Cats’ relegation to the Championship could be confirmed as soon as 26 April – with five games remaining.
Sunderland were not helped by an injury to Bryan Oviedo, which cut short the defender’s afternoon, while Larsson’s contentious straight red card for going over the top of the ball on Herrera ended any realistic chance of a win before the interval.
Larsson, who was furious with referee Craig Pawson’s decision, now faces a suspension for his first Premier League dismissal in what was his 278th appearance in the competition.
Moments before the red card, Victor Anichebe had been denied by United’s Argentina keeper Sergio Romero, who was starting in place of the injured David de Gea.
Jermain Defoe went close from 20 yards after the interval but the Black Cats have lost six of their last seven games and look drained of any confidence.
Shaw earns a pat from Mourinho
Jose Mourinho made five changes for his side’s 50th competitive game of the season but while keeper De Gea’s absence was down to injury, the United boss opted to rotate players ahead of Thursday’s Europa League quarter-final first leg with Anderlecht.
Luke Shaw made a surprise return just days after Mourinho had questioned the full-back’s commitment and delivered a polished performance as the Red Devils stretched their unbeaten Premier League run to 21 games.
Shaw recovered from an early booking, awarded for flying in behind on Didier Ndong, to offer width and attacking threat down the left.
In front of watching England manager Gareth Southgate, he set up a great chance for Marouane Fellaini, made captain for the day four months after being booed by his own fans.
And Shaw’s lively contribution also included an attempt on goal and the pass to Mkhitaryan to make it 2-0.
It was telling when Mourinho gave the 21-year-old a deserved pat on the back when he was replaced, with United in total control, soon after Ndong accidentally stood on his ankle.
Ibrahimovic’s opening goal was a delight, spinning away from Billy Jones before bending home from outside the area.
No Sunderland player had touched the ball when Mkhitaryan doubled the lead 45 seconds into the second half with a low shot, while substitute Rashford completed a fine counter-attack to slot his first league goal since 24 September.
underland boss David Moyes: “I don’t want to blame referees for my position and us losing. Today the result was helped by the referee. Manchester United were playing well but the red card was a decision that went against us.
“[Before United scored] We were hanging in the game and staying in the game and trying to do our best. We gave away a poor goal and I thought we needed to get a lot closer. When we went down to 10 men it made it a lot harder.
“We keep going. We have another home game next Saturday and we have to try and win it. We do some good things but just lack a bit of quality but it’s not for the want of trying. The boys are doing everything they can.
“The hardest thing as a manager is losing and we’re losing a lot. The players care and want to do well and we’re not doing as well as we should be.”
Manchester United manager Jose Mourinho: “We want to fight in the Premier League until it is mathematically impossible. The Premier League we cannot win, but Europa League we can.