James Collins headed West Ham in front after 10 minutes and six minutes later Chelsea midfielder Maniche was sent-off.

Ivorian Didier Drogba equalized for Chelsea in the 29th minute and strike partner Hernan Crespo grabbed the lead 2 minutes later.

Second-half goals from defenders John Terry and William Gallas sealed the win for the Blues and raised their tally to 82 points with five games left to play.

Second-placed Manchester United, who face Arsenal later on Sunday, are 10 points adrift of Chelsea.

Collins rose unchallenged to a Yossi Benayoun corner-kick in the 10th minute and buried home a header past keeper Petr Cech.

Six minutes later, a rash tackle from Maniche on Lionel Scaloni earned him his marching orders.

Jose Mourinho's side fought back and grabbed the equalizer when Drogba latched on to Frank Lampard's long pass and fired home from a tight angle after his initial effort was denied by Collins.

Two minutes later Drogba turned provider even if by coincidence.

The Ivorian rifled a drive that was deflected off Collins into the path of Crespo who notched home from close range.

The comeback was overwhelming for the Hammers who conceded two more goals after the break.

Chelsea skipper Terry extended the lead with a brilliant bouncing effort after Gallas hit the bar in the 54th minute.

Gallas registered a goal of his own in the 69th minute to cap a spectacular comeback for the defending champions.

Later on Sunday, Liverpool beat Bolton 1-0 thanks to Robbie Fowler's goal on the stroke of halftime.