Hernan Crespo scored within seconds of coming on as a substitute and Didier Drogba lashed home the goal of the game to give champions Chelsea a stirring 3-1 win at West Ham United on Monday.
Chelsea dominated the Premier League London derby after taking a 25th minute lead when England midfielder Frank Lampard volleyed home against his former club at Upton Park.
They were pegged back just after the re-start by Marlon Harewood's equaliser but Argentina's Crespo rounded Roy Carroll to restore Chelsea's lead in the 61st minute and Drogba of the Ivory Coast drove in the third with 10 minutes to go.
Victory gave Chelsea a 14-point lead over nearest rivals Manchester United, who take on Arsenal at Highbury in the showcase match on Tuesday.
A fourth win from their four festive season matches was just what Chelsea had wanted in their canter towards a second consecutive league title.
"That's what we set out to do," Lampard told Sky Sports. "We don't want to let up, we want to keep winning games, keep the gap at the top and if anything make it bigger."
Lampard, who had come up through the ranks at West Ham before being sold to Chelsea for 11 million pounds ($18.95 million) in 2001, was booed by his former fans in east London.
Asked about the reception at a ground where his father was also a favourite for many years, Lampard said: "It wasn't great. I expected that. I would like to come back here and get a bit of respect, but not many will give me that here."
The only other sour notes for Chelsea were the injuries which forced off Ghana midfielder Michael Essien after 13 minutes, and also Crespo, whose goalscoring cameo lasted 23 minutes.
Czech forward Milan Baros converted a late penalty to give Aston Villa a 2-1 win over West Bromwich Albion in the Midlands derby earlier in the day.
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