Chelsea made it six wins from six games after Hernan Crespo and Arjen Robben guided the Premier League champions to a 2-0 victory at Charlton Athletic on Saturday.
Jose Mourinho's side hit the woodwork twice before Crespo headed them into a 55th minute lead and Robben curled in the second just five minutes later to seal the win.
Victory left Chelsea six points clear at the top of the table, having scored 12 and conceded no league goals this season as they build on their Community Shield win over Arsenal.
West Ham United won 2-1 at Fulham in the other London derby, Portsmouth were held 1-1 at home by 10-man Birmingham City and there was heartbreak for Sunderland after West Bromwich Albion scored in the final seconds for a 1-1 draw.
Tottenham Hotspur drew 1-1 at Aston Villa after their England striker Jermain Defoe missed a first-half penalty and Ireland forward Robbie Keane scored a superb late equaliser.
Premier League action continues on Sunday, with Liverpool hosting Manchester United in the day's showcase game, while Arsenal meet Everton on Monday at Highbury.
None of those sides can yet catch a Chelsea team who are runaway favourites to retain their title - having waited 50 years to win only their second championship last season.
Mourinho's assistant Steve Clarke told Sky Sports News: "There's no comfortable victories in the Premier League.
"The first half was an even game. At halftime we had a little word with the lads and asked them to step up a gear - and I think it showed in the second half that we were on top.
KILLING GAME
"When you know you're in the ascendancy, you have to kill the game at that moment - and we did that."
Defeat for Charlton, who stay second in the table on 12 points pending Sunday's games, was their first after having won all of their four previous league matches this season.
Charlton boss Alan Curbishley said: "We'll take it on the chin today. We've been doing well and we start again on Tuesday in the League Cup game (against Hartlepool)."
Crespo gave Charlton an early warning when the Argentine striker sent a 20th minute shot onto the post and France defender William Gallas hit the woodwork after the break.
Ghana midfielder Michael Essien, on impressive form, picked out Crespo for their first goal, while Robben showed the range of his skills with a superb shot for the second.
West Ham striker Marlon Harewood, who scored a hat-trick in Monday's 4-0 win over Aston Villa, was a match-winner again at Craven Cottage. He scored a fine solo goal after 47 minutes and then saw a shot fly in off keeper Tony Warner as an own goal.
Birmingham settled for a point at Fratton Park after having midfielder Nicky Butt dismissed just before the break for kicking out at Uruguayan striker Dario Silva.
It was a very different point for Sunderland, who came within seconds of ending a run of 20 straight defeats in premier league games with a morale-boosting win when Hungary midfielder Zoltan Gera headed West Brom's equaliser in the fourth minute of stoppage time.
