Old Trafford was the scene as Pep Guardiola and Jose Mourinho took their rivalry to the Premier League.
The pair clashed often when in charge of Real Madrid and Barcelona but and it was first blood to the former Barca manager.
Kevin de Bruyne finished neatly to put the Blues ahead after 15 minutes.
Kelechi Iheanacho tapped in to double the score for City in the 36th minute.
But United got lucky when City’s keeper Claudio Bravo let a free kick slip through his fingers, allowing Zlatan Ibrahimovic to score for United.
The Blues held on at 2-1 to make it four wins from four starts.