Frank Lampard struck twice as champions Chelsea beat West Brom to return to the Premiership summit in emphatic fashion.
Lampard broke the deadlock after 23 minutes, firing home after good work by Didier Drogba and a clever dummy from new £24.4m signing Michael Essien.
Joe Cole scored a second before the interval after a determined run from another new boy, Shaun Wright-Phillips.
Drogba added a third after the break, before Lampard scored his second from close range with 10 minutes left.
As expected, Chelsea manager Jose Mourinho gave first starts to his expensive summer captures Essien and Wright-Phillips.
And they both made key contributions as the champions established a comfortable lead at the interval.
Mourinho also gave a rare start to goalkeeper Carlo Cudicini and rested first choice Petr Cech.
Chelsea went ahead after 23 minutes as West Brom paid the full price for a piece of carelessness from defender Thomas Gaardsoe.
His pass sold Neil Clement short, and when Drogba crossed, Essien dummied for Lampard to control and fire a powerful finish past Chris Kirkland.
And Wright-Phillips, who had been quiet in the first half, showed great determination to set up Cole for Chelsea's second on the stroke of half time.
Albion defender Paul Robinson thought the ball was running to safety, but Wright-Phillips stole in and crossed for Cole to score with ease.
Chelsea continued to dominate after the break, and Cole almost added his second when he shot across the face of goal after 54 minutes, with Drogba just unable to get the final touch.
Kirkland then made a fine double save from Drogba's header and Essien's powerful follow up as Chelsea pressed for a third goal.
And it needed more desperate defending to halt Drogba, who then set up Essien for a shot which was blocked.
Chelsea's third was only a matter of time, and it came after 67 minutes when Asier del Horno turned the ball back for Drogba to hit the target from close range.
The visitors' cause looked hopeless, but boss Bryan Robson sent on Nathan Ellington for his debut as replacement for Jonathan Greening - but Chelsea responded by replacing Drogba with Hernan Crespo.
The champions were rampant and it was no surprise when Lampard struck again with 10 minutes left, firing past Kirkland after good work by substitute Arjen Robben.
Chelsea manager Jose Mourinho:
"We played well. We looked very confident and compact, there were no defensive problems and we used the ball very well.
"We had control of the game and always looked dangerous. The result expressed what happened on the pitch.
"We were better than against Arsenal, the team played better football."
West Brom boss Bryan Robson:
"For me we gifted Chelsea the game.
"It is disappointing in that we have been defending really well but individual errors cost us.
"We kept our shape well and made it difficult to break us down.
"But we gifted them two goals and if Real Madrid came here and gave two goals away they would not come back into the game."
Chelsea: Cudicini, Johnson, Terry, Gallas, Del Horno, Makelele, Essien, Lampard, Joe Cole (Robben 69), Wright-Phillips (Duff 79), Drogba (Crespo 71).
Subs Not Used: Cech, Ricardo Carvalho.
Goals: Lampard 23, Joe Cole 43, Drogba 68, Lampard 80.
West Brom: Kirkland, Albrechtsen, Gaardsoe, Clement, Robinson, Greening (Ellington 71), Scimeca, Chaplow, Johnson (Inamoto 60), Kamara, Kanu.
Subs Not Used: Moore, Earnshaw, Kuszczak.
Ref: M Halsey (Lancashire).