Manchester City avenged last seasons derby defeat with an assured performance over Manchester United at the Etihad.
David Silva opened the scoring after just 11 minutes when Bernardo Silva squared the ball across goal from Raheem Sterling's cross.
Sergio Aguero slammed in a second shortly after half time as United looked to be sinking without trace. Anthony Martial carried on his rich vein of form to reduce the deficit to a goal, but City were not done yet.
The home side added a third late on when they strung together 44 passes before sub Ilkay Gundogan slotted home following another cross from Bernardo Silva to wrap up the points.