Robin Van Persie curled in a late free-kick to give Manchester United a 3 - 2 victory over rivals City.
The win puts the Reds six points clear of the Sky Blues at the top of the Premier League.
Man United had taken control of the game in the first half thanks to Wayne Rooney.
The number 10 slotted past Joe Hart on the break to open the scoring after a quarter of an hour.
And the former Evertonian made it two when he converted a Rafael cross on the half hour mark.
City came out all guns blazing after the break and pulled one back when Yaya Toure stroked in after a goalmouth scramble in the United box on 60 minutes.
And Roberto Mancini's side pulled themselves level five minutes from time when Pablo Zabaleta smashed home unmarked from the edge of the box.
But Alex Ferguson's team were to have the last laugh as Carlos Tevez fouled Rafael 25 yards out.
And Van Persie stepped up to curl the ball past Joe Hart - although Samir Nasri should have done much better in the wall.
There was still time for late controversy as Rio Ferdinand appeared to be struck by an object thrown from the Man City end as he celebrated the winner.