City ran out 2-1 winners and gave United a golden chance of once again getting in front of Chelsea in the table as soon as they slip up again.
Carlo Ancelotti's side had a lucky break to get their noses in front when Emmanuel Adebayor scored an own goal, but the Togo international then scored at the correct end to level things up.
And then it was down to United old boy Carlos Tevez to work his magic with a free kick that gave City the points and left Chelsea nervously over their shoulders as United prepare to pounce.