Diego Costa and Eden Hazard scored in the first half before Victor Moses added the gloss late on in the second.
The Blues stormed Leicester in the opening exchanges and they were rattled.
Exposed again from a set piece, Claudio Ranieri’s men were in disarray.
Costa scored after just seven minuted as he peeled off his man for a corner and wandered unmarked to the back post.
He fired beyond Kasper Schmeichel who had no chance.
Hazard doubled the lead after 33 minutes as he drove through the midfield -via a bobble and missed tackle – to then beat Schmeichel and slot into an empty net.
David Luiz smashed the post from a free kick as Chelsea threatened to run riot.
Leicester were better in the second half and came close when Luiz nearly put through his own net.
But Moses ended any hope of a comeback with an 80th minute goal after a nice link up with substitute Michy Batshuayi.