Florent Malouda set the Blues on their way after only six minutes, with Drogba's free-kick extending the lead on the stroke of half-time.

It was more one-way traffic after the restart, as the Ivory Coast striker netted from close range with Frank Lampard making it 4-0 just after the hour.

Drogba's deflected effort and a last-minute strike from Malouda sealed an emphatic win for the champions, who put last week's 3-1 defeat by Manchester United in the Community Shield at Wembley firmly behind them.

Despite being outplayed, West Brom and their manager Roberto Di Matteo, the former Chelsea midfielder, deserve credit for continuing to display some good passing football, but which tellingly lacked a cutting edge in the final third.

Chelsea had got off to a flying start when they took the lead after only six minutes.

Malouda was tripped by Pablo Ibanez on the edge of the West Brom box.

Keeper Scott Carson spilled Drogba's free-kick straight to John Obi Mikel, whose follow-up effort was blocked. The ball then dropped straight to Malouda, who could not miss.

The champions were in full flow, with Ashley Cole whipping a low ball across the six-yard box after another surge down the left.

However, the conditions worsened, and fit again Chelsea keeper Petr Cech had to be at full stretch to touch away Graham Dorrans' deflected effort.

The visitors, who finished second behind Newcastle in the Championship last season, continued to try to take the game to Chelsea, putting together some promising passing moves.

Czech striker Roman Bednar smashed a fine finish into the roof of the Chelsea net on 18 minutes, but the offside flag had already gone up for what looked a marginal decision.

Cole then drew some predictable jeers from the travelling fans when he went to take a throw-in - but the boo-boys were soon drowned up by the home faithful showing the England defender their full support.

After a drop in tempo, Chelsea slowly started to find their rhythm again.

Gabriel Tamas fouled Drogba, giving Chelsea another chance to deliver a ball into the West Brom box.

Lampard struck his 20-yard shot well and Carson parried, but this time Malouda could not keep his follow-up on target as he sent a looping header over.

It was, though, 2-0 just before the break.

Youssouf Mulumbu tripped Michael Essien and this time Drogba smashed his free-kick through the wall and into the bottom corner.

The conditions improved for the second half, allowing both teams to pass the ball quickly.

On 53 minutes, Scotland midfielder Dorrans chipped a free-kick over the wall, but the ball dropped onto the top of the net.

Chelsea then moved 3-0 ahead when Drogba bundled in his second.

John Terry flicked Malouda's inswinging corner goalwards and Mulumbu hacked it off the line, but the ball was not cleared and Drogba, who won the Golden Boot with 29 goals last season, was alert to smash it in from close range.

Lampard walked in a fourth on 63 minutes after a clever exchange between Nicolas Anelka and Cole down the left.

The England midfielder, who had been carrying a slight ankle problem, was then replaced by Yossi Benayoun, as the Israeli made is debut following a summer move from Liverpool - who were described as a "small club somewhere north of the M25" by Chelsea chairman Bruce Buck in his programme notes, hitting back at comments by Joe Cole following his free transfer summer move to Anfield.

On 68 minutes, Drogba completed his hat-trick with a 20-yard effort which cannoned off Tamas and flew into the bottom corner past a wrong-footed Carson.

The Ivory Coast striker was then given a well-deserved break when he was replaced by countryman Salomon Kalou.

Malouda whipped a 20-yard free-kick over the wall and bar, while Alex flicked a rising shot from Chris Brunt over the bar to deny the visitors a late consolation. And the hosts were still not finished as Malouda rounded Carson to knock in number six off the post in the final minute.