Substitute Kai Havertz scored a late winner as Chelsea recovered to record a dramatic victory over West Ham, though David Moyes was left furious by a "scandalous" decision to rule out a 90th-minute Hammers equaliser.
Maxwel Cornet pounced after Edouard Mendy parried the ball into his path, but referee Andrew Madley was told to consult the pitchside monitor and then ruled Jarrod Bowen had fouled the Chelsea goalkeeper in the build-up.
The Hammers frustrated Chelsea in a first half that saw plenty of home possession but no shots on target for either side, and looked to have executed their gameplan to perfection when Michail Antonio scored after 62 minutes, bundling in from close range after Mendy failed to deal with a corner.