The champions are now 14 points behind leaders Liverpool, who comfortably beat Bournemouth 3-0 earlier in the day.
Manchester United have now comfortably negotiated tricky fixtures against Tottenham Hotspurs and Manchester City to move up to fifth on the table, five points behind fourth placed Chelsea.
In a blistering start to the game, Manchester United created the first real opening when Anthony Martial played Daniel James through in the third minute but the Welshman’s powerful effort was palmed away by Ederson in the City goal.
Ederson was once again called into action in the ninth minute when Marcus Rashford put through Jesse Lingard on the left side of goal but the Brazilian goalkeeper stuck out a leg to block his shot.
Another United attack brought the best out of Ederson, who reacted swiftly to bat away a fierce Martial strike following some good work from James and Rashford in the 15th minute.
The visitors were awarded a penalty following a VAR review after Bernardo Silva tripped Rashford in the box, and United’s top scorer picked himself up to send Ederson the wrong way for the opener in the 23rd minute.
Rashford twice came close to doubling United’s tally in the space of a minute; first shooting wide from a good Fred pass on the counter before clipping the crossbar with a delightful effort in the 26th minute.
The visitors continued to overwhelm the champions with waves of attacks, and it paid dividends in the 29th minute when Martial beat Ederson with a sweeping effort at his near post.
City’s best chance of the first half came in the 37th minute when Gabriel Jesus’ diving header from Kevin de Bruyne’s cross went wide of the right post.
Substitute Nicolas Otamendi, on for the injured John Stones, brought the champions back into the game when he headed in Riyad Mahrez’s corner in the 85th minute.
Two minutes later, De Gea had to be on the alert to prevent a swift equaliser, as he pushed away Mahrez’s low effort to preserve United’s lead.
