After Peter Odemwingie had given Albion a 17th-minute lead, the Blues replied with three first-half goals from Didier Drogba, Salomon Kalou and Frank Lampard.
Albion started brightly, and their opener was richly deserved. Jerome Thomas' ball to Odemwingie took a slight ricochet off John Terry, but the pass still found its intended target, and Odemwingie sprinted into the area before deftly flicking the ball over the advancing Petr Cech.
However, Chelsea hit back in the 22nd minute. A string of passes culminated in Ashley Cole's ball down the left finding Kalou, who delivered a low cross that goalkeeper Scott Carson failed to push away. Nicky Shorey's attempted clearance at the far post found Drogba, who slid the ball home.
Four minutes later, Chelsea were ahead, albeit Carson did not help his side's cause again. The Albion goalkeeper was low down to a 25-yard Drogba drive, but only succeeded in parrying the ball into the path of Kalou, who passed his shot into the net with an angled shot.
Chelsea put the points to bed on the stroke of half-time. Drogba dispossessed Chris Brunt and sent Kalou away down the left. He had time and space to pick out Lampard, who drilled home a low right-footed shot.
Source: PA
Source: PA