Chelsea tightened their grip on the Premiership title with a comfortable win over Crystal Palace.
A trademark long-range Frank Lampard strike put Chelsea ahead only for his error to allow Aki Riihilahti to level.
Andy Johnson had a chance to give the visitors a shock lead but he angled a shot wide before Joe Cole's well-struck effort put Chelsea back in front.
Mateja Kezman grabbed two late Chelsea goals with his first coming after Gabor Kiraly let a shot through his grasp.
Palace had spent five days in Cyprus to carry out warm-weather training in the build up to this game and it proved useful at a sun-bathed Stamford Bridge.
The visitors kept Chelsea at arms length in the early exchanges as the home side patiently probed away trying to prise a goal-scoring opening.
Cole provided Chelsea's biggest threat as he continued his impressive recent form and his tenacious attitude and vision helped create chances for Didier Drogba and Damien Duff.
Riihilahti's equaliser for Palace proved to be in vain
Duff's had the clearer sight of goal but his effort was blocked by Kiraly, who had little chance when Lampard's arrowed in a powerful 30-yard shot for Chelsea's opener.
But, in his 300th career league game, it was Lampard's error at the other end which allowed Palace to level as he mis-kicked a near post clearance from a Wayne Routledge corner.
The ball found it's way into the Chelsea six-yard box where Riihilahti was lurking to sidefoot in a left-foot shot to earn some reward for the determination and effort of Iain Dowie's players.
It was only the fourth Premiership goal Chelsea have conceded at home this season and sparked them into a flurry of action.
Drogba had a bicycle kick smartly saved to his left by Kiraly and Ricardo Carvalho headed wide before Palace spurned a glorious chance at the other end.
Johnson had a clear sight of goal but shot wide after keeper Petr Cech's punched clearance was quickly played back into the Chelsea box.
And, although Palace started the second half brightly, the miss proved crucial as Cole ran onto a Gudjohnsen pass and struck a true angled shot into the far corner of Kiraly's net.
Chelsea played within themselves as Palace tired and Jose Mourinho had the luxury of bringing on Dutch winger Arjen Robben, who has been out with a broken foot.
Kiraly allowed a hopeful Kezman shot through his grasp for Chelsea's third and the Blues striker bundled in a late goal to move Chelsea a big step closer to their first title in 50 years.
Chelsea midfielder Joe Cole:
"I'm just so excited. I can't stop looking at the fixture list and thinking if we win this game, this game and this game, then...
"But it's important to check yourself and think about winning the next game."
"Even after winning 4-1, we still felt there were improvements we could have made."
Crystal Palace manager Iain Dowie:
"With a 2-1 lead at half-time, it would have been better but Andrew has done well for us this season, so I'm not going to blame him for that miss.
"The scoreline was probably harsh but you can't defend like we did for the second and fourth goals.
"Manchester United, Arsenal and Chelsea are all good sides but Chelsea are capable of beating you in different ways. Now the other two have everything to do to catch them."
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.
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.
Ref: P Dowd (Staffordshire).