Michael Essien set the ball rolling before a brace by Didier Drogba and strikes from Joe Cole, Salomon Kalou and Andriy Shevchenko completed the rout.
It was a result better than anything Jose Mourinho achieved at the club - his best was a 5-1 drubbing of Bolton Wanderers.
Chelsea's first effort on goal came via Alex on seven minutes. The Brazilian headed a deep ball towards City's far post where Kalou was inches away from tucking the ball home.
City broke quickly on 12 minutes when a misdirected Alex pass was intercepted and the ball was sent forward to Georgios Samaras.
The Greek striker hit a half-volley which forced Petr Cech to make a smart, low save to his right
Alex was involved again on 15 minutes but he put a Frank Lampard corner over the bar with a strong header.
Seconds later Chelsea took the lead through Essien. The Ghana midfielder picked up an excellent defence-splitting pass from Lampard on the right and raced into City's penalty area, before slotting home a daisy-cutter across the body of the despairing dive of Joe Hart.
On 21 minutes Martin Petrov produced a fine 25-yard free-kick which Cech did well to dive to his right and tip the ball around his post.
Richard Dunne was forced into a fine defensive header to deprive Drogba from getting on to Cole's fine right-wing cross.
Chelsea rammed home number two when Drogba raced onto Lampard's brilliant curling pass which dissected the City defence.
The Ivory Coast striker drilled the ball home through Hart's legs from just inside the City area.
Stephen Ireland missed a sitter on 38 minutes when he screwed wide a right-footer from just outside the Chelsea penalty area.
A blistering Petrov free kick on 52 minutes signalled City's attempt to get back into the game early in the second half.
But it was Chelsea who scored to seal the game on 56 minutes.
Drogba latched on to the ball ten yards out from Hart who could only parry away a Lampard drive and the striker hammered home a fierce right-footer.
The goal came from a rampaging left-wing run by Paulo Ferreira who crossed from the byline to Kalou whose own shot was closed down.
It fell to Lampard to hit the ball on target and Hart produced a fine save, but sadly for him the ball went to Drogba for his second goal of the game.
Drogba then missed an open goal a minute later when Hart again produced a fine save from another Lampard drive only to see the ball fall to the Ivorian, who screwed it wide.
Bit City were torn apart on 60 minutes when Cole picked up a fine glancing header by Drogba and raced through the City rearguard before toe-poking home a right-footer past a hapless Hart for number four.
With Chelsea in complete control, number five duly came on 75 minutes when Essien slid the ball to Kalou on the right and the Ivory Coast hitman coolly slotted home past Hart.
Substitute Andriy Shevchenko completed the scoring with a minute remaining when he rammed home a fine drive across the face of Hart.