Didier Drogba's first-half goal tonight extended Chelsea's lead at the top of the Barclays Premiership to 11 points.

The Ivory Coast striker put Chelsea a step closer to their first title triumph for 50 years when he finished off a flowing three-man move in the 26th minute.

Frank Lampard sent Damien Duff free on the left with an exquisite through ball and the Irishman delivered a low cross for Drogba to turn home from six yards.

Chelsea dominated the game from start to finish and West Brom had little joy in attack where John Terry and Robert Huth were always in command.

Chelsea made their intentions were made clear in the first minute as Terry almost put them a head with a header from Duff's corner.

Unfortunately for Jose Mourinho's men, Eidur Gudjohnsen turned the ball wide when attempting to deflect the header into the net.

Drogba should have broken the deadlock in the fifth minute but his shot on the turn from six yards was too weak to beat Russell Hoult in the visitors' goal.

Drogba then sent a free-kick by Lampard over the bar as West Brom struggled to cope with the rampaging Chelsea forward line.

Joe Cole was causing Albion all sorts of problems down the right flank and in the 11th minute he provided two crosses which really should have brought the Londoners some reward.

As it happened, neither Drogba nor Gudjohnsen could get close enough to finish them off and in the 16th minute Duff was inches wide with a left-foot piledriver from the edge of the box.

In the 22nd minute, Lampard put Drogba in the clear but the Ivory Coast striker could not lift the ball over the advancing Hoult and into the empty net.

Albion offered little in response although they had the ball in the net twice in the opening period - both attempts clearly offside.

Chelsea made the crucial breakthrough when Lampard carved open the static West Brom defence with an inch-perfect pass for Damien Duff.

The Republic of Ireland international had been a real threat on the left and he sprinted clear before delivering a low cross that Drogba converted easily from six yards out.

The goal settled Chelsea's nerves and they began to play with more control while Albion relied on the occasional foray into the Londoners' half.

The closest they came to scoring was a feeble header from Kevin Campbell from a right-wing cross by Ronnie Wallwork.

Chelsea continued to search for more goals and Cole sent Drogba clear again in the 33rd minute but this time, although he rounded Hoult, he was unable to prevent Martin Albrechtsen clearing the loose ball.

Cole then tried his luck from 20 yards as Chelsea continued to exert an iron-like grip on proceedings.

The former West Ham midfielder was unlucky not to do better with a 20-yard effort which Hoult was able to collect without fuss.

There was no respite for West Brom when the second half got underway, even though left-back Neil Clement tested Petr Cech with a long-range effort within a minute of the restart.

After that, normal service was resumed as Chelsea poured forward at every opportunity.

In the 48th minute their hunger for more goals was almost satisfied when Lampard again sent the impressive Duff clear on the left flank.

Hoult, who paid for his indecision by staying on his line for the first goal, opted to intercept Duff's subsequent cross as the Irishman again looked to find Drogba inside the six-yard box.

Two minutes later, Duff forced Hoult to dive low to his right to prevent him scoring Chelsea's second goal.

That should have arrived on the hour when Lampard was again the architect of another stunning Chelsea move.

This time the England international midfielder played a slide-rule pass to Drogba who turned Thomas Gaardsoe on the edge of the box - only to send his low drive around the outside of the right-hand post.

In the 63rd minute, Lampard sent a long-range free-kick just a foot over Hoult's crossbar as the pressure continued unabated on the Albion goal.

Chelsea should have wrapped the game up in convincing fashion in the last 12 minutes but Drogba was guilty of two glaring misses.

First he headed wide from Cole's cross and then blasted the ball over the bar from six yards after Duff again found him with a low cross from the left.

Chelsea were more than content to play out the closing stages in the knowledge they now have an almost unassailable lead at the top of the table.

Teams

Chelsea Cech, Paulo Ferreira, Terry, Huth, Gallas, Makelele, Cole (Kezman 86), Lampard, Duff (Smertin 90), Gudjohnsen (Jarosik 74), Drogba.

Subs Not Used: Ricardo Carvalho, Cudicini.

Goals: Drogba 26.

West Brom Hoult, Robinson, Gaardsoe, Clement, Albrechtsen, Gera, Richardson (Greening 86), Wallwork, Horsfield (Earnshaw 83), Campbell, Kanu.

Subs Not Used: Scimeca, Moore, Kuszczak.

Booked: Clement.

Att: 41,713

Ref: N Barry (N Lincolnshire).