Carlos Tevez scored twice to give Man City victory over his previous club, Man Utd, in their Carling Cup semi-final first leg game.
It looked like United were in the best position to take the win when Ryan Giggs slotted the ball home early on.
But Tevez equalised for City with a controversial penalty, after Rafael da Silva fouled Craig Bellamy.
Tevez sealed the game at 2-1 with a headed goal from close range early on in the second half.
Tevez's first goal caused a bit of a stir among fans.
Rafael da Silva clearly fouled Craig Bellamy outside the area, but referee Mike Dean waited until the pair were inside the box before calling for the penalty.
City faced a tense time in the closing minutes.
Goalie Shay Given saved attempts from United's Wayne Rooney three times, and Michael Owen's shot was knocked away from goal by City's Nedum Onuoha.