City were unplayable in the first half and raced into a 4-0 lead after just 25 minutes. Raheem Sterling put them ahead in the 4th, running onto an effort at the far post, before Aguero’s 25-yard stunner in the 13 minute13 into the top corner made it 2-0, moments after he had missed a sitter from close range.
Aguero turned home his second after a Ross Barkley mistake in the 19th minute and Ilkay Gundogan put the game well beyond Chelsea with a low shot into the bottom corner from the edge of the box in the 25th minute.
Aguero completed his hat-trick from the spot in the 56th minute, meaning he has 43 goals in 64 games against the big six, 22 more than any other player since he moved to the Premier League in 2011.
Sterling made it 6-0 from close range after fine team move in the 80th minute, and the result means City go back to the top of the Premier League on goal difference, having played a game more than Liverpool. Pressure grows on Maurizio Sarri and Chelsea, who drop to sixth, a point behind fourth-placed Manchester United.