But Anthony Martial's equaliser from the penalty spot on 57 minutes, after substitute Romelu Lukaku had been fouled by goalkeeper Ederson, gave United a flicker of hope.
Paul Pogba will not join up with France during the worldwide break after missing the Manchester derby through injury.
The distance between the two teams is already 12 points, an insurmountable obstacle for the Red Devils, and we are only in mid-November.
Pogba would have given United the ability to stretch the game, but without the Frenchman, Mourinho could have given his team more adventure and ambition by selecting Juan Mata. Mourinho's team have kept just one clean sheet in the league this season and David Silva's strike in the 12th minute was the seventh time in 12 games that they have conceded first and the sixth time in nine they have conceded inside the first 20 minutes. Whenever they had the ball, there were huge gaps behind them and City were able to snuff out every United attack for the first hour of the game.
"Cristiano Ronaldo is a player who moves to the left more, but he moves around a lot and in fact, the goal I scored in Manchester came from his cross from the right".
"I consider the performance of my team one of mistakes rather than a bad performance", Mourinho said. There can be games where you win 3-0 or 4-0 and everyone's happy but what have you learnt from the game itself?
But you've got to admit, that still is pretty amusing from the England global. "We won't lose that because of a defeat". "I can imagine when the result was 2-1, if we bring a fresh Fellaini on, I think they (Man City) would be in big, big trouble". But City's scouts have so far failed to find a player capable of replacing one of the most important cogs in Guardiola's team. "I was on the bench for that game and I was itching to get on", he said.
'The way the fans were supporting us, even at 2-0 down, they stayed with us and backed us throughout the game and that spurred us on'. The one thing he hasn't delivered answers to are the same issues which have plagued United so far this season and leave them languishing outside the top four.