Joe Cole responded to the long-awaited return of Arjen Robben by inspiring Chelsea to a convincing victory against Crystal Palace as Jose Mourinho's side took another major step towards the title.

Cole has profited from Robben's injury-induced absence over the past couple of months and his vital 54th-minute strike against Palace was proof of his recent renaissance.

After all, Chelsea were struggling to make their advantage count at that stage, with Frank Lampard's strike cancelled out by Aki Riihilahti, while Andrew Johnson had spurned a clear opening.

Cole's impact was nevertheless decisive with his sixth goal of the season and when Robben made his comeback as a substitute after seven weeks out, it was Damien Duff - not Cole - who made way.

Robben's return could also still threaten Cole's starting place, with the Dutchman immediately involved as he played a minor role in Chelsea's third goal.

However, substitute Mateja Kezman had Palace keeper Gabor Kiraly to thank for his embarrassing blunder in allowing his shot to slip through his grasp, before the striker also hit a late fourth.

As a result, Chelsea now require at most 14 points from their eight remaining league games to ensure their first title for 50 years.

Cole's all-round game has matured significantly under Mourinho's demanding tutelage over the past few months. Indeed, Sven-Goran Eriksson must now weigh up whether to use him in England's World Cup qualifier against Northern Ireland next weekend.

Cole had provided Chelsea's main early impetus, with defender Gonzalo Sorondo and keeper Kiraly having to be alert to the dual threat of both Chelsea's wingers.

It was still largely a scrappy affair at this stage, with both managers on their feet to bark instructions at their side.

Not that they bore much resemblance to each other, with Iain Dowie opting for shorts and a T-shirt in the bright sunshine, while Mourinho choosing a suit and woollen scarf.

The Chelsea boss' side continued to hold the upper hand, albeit marginally, until Palace committed the cardinal sin of allowing Lampard far too much space outside the penalty box.

Even though the England midfielder was still 25 yards out from goal, he took aim with 28 minutes gone and powered a superb drive into the corner of the net.

Chelsea continued to threaten, with Glen Johnson striking the side netting, Didier Drogba volleying just wide and Lampard failing to make propert contact with a diving header.

Palace nevertheless made Chelsea pay for an uncharacteristic defensive lapse just before the break.

Chelsea failed to deal with a weak, low corner from Wayne Routledge, with Lampard missing his kick at the near post.

The ball sped across the turf to Riihilahti, whose shot from just six yards out deflected slightly off Ricardo Carvalho and into the net.

Palace were indebted to Kiraly for producing a fine reaction save to tip Drogba's overhead kick around the post, while Carvalho also headed narrowly wide.

However, they should have seized the lead before the break, only for Johnson to scuff his shot wide when presented with a clear opening from Sorondo's mis-hit cross-shot.

Palace continued to threaten after the restart, with Tom Soares' shot being blocked by Carvalho and Routledge going down in the penalty area to no avail.

However, while Robben's arrival was imminent, Cole was not about to give up his place in the side without a fight.

The midfielder scampered downfield as Chelsea counter-attacked and, despite initally tripping over, he hauled himself to his feet and timed his run perfectly to race onto Eidur Gudjohnsen's pass.

Cole briefly weighed up his options before striking his shot into the far corner, leaving Kiraly helplessly rooted to the spot.

Mourinho initially turned to Tiago to shore up his midfield as Drogba came off, but Robben was finally brought on with 17 minutes left.

The Dutchman even played a minor role in the build-up to Chelsea's third goal, although there was little obvious danger until Kiraly's blunder allowed Kezman's shot to slip through his grasp.

Robben almost scored himself in the closing stages, but Kezman rounded off the scoring in the last minute as he converted a loose ball from close range after a scramble in the Palace penalty area.

Cole was nevertheless deemed man of the match and rightly so. Chelsea are finally not only reliant on Robben.

Teams

Chelsea Cech, Paulo Ferreira, Terry, Ricardo Carvalho, Johnson, Makelele, Cole, Lampard, Duff (Robben 74), Drogba (Tiago 63), Gudjohnsen (Kezman 77).

Subs Not Used: Cudicini, Huth.

Booked: Terry.

Goals: Lampard 29, Cole 54, Kezman 78, 90.

Crystal Palace Kiraly, Granville, Sorondo (Freedman 74), Hall, Boyce, Routledge (Torghelle 73), Riihilahti (Watson 88), Hughes, Soares, Leigertwood, Johnson.

Subs Not Used: Speroni, Borrowdale.

Goals: Riihilahti 42.

Att: 41,667

Ref: P Dowd (Staffordshire).