Loic Remy scored Chelsea's winner for the second straight game to send them seven points clear at the top of the Premier League courtesy of a 2-1 win over Stoke City.
Charlie Adam struck from inside his own half to cancel out a penalty from Eden Hazard, who supplied Remy for the deciding goal after a mistake from Asmir Begovic.
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The Blues could be relying on the Frenchman for the rest of their title run-in after Diego Costa aggravated his hamstring injury shortly after coming on as a half-time substitute.
With fitness doubt Costa not risked from the start, Remy led the Chelsea line and would have put them ahead on two minutes had it not been for Begovic reacting well to claw his deflected shot clear.
Hazard created a couple of chances for himself, shooting high and then tamely at Begovic after mazy runs, before combining with Willian to provide Oscar with a golden opportunity which he rolled wide of the post.
The dominant hosts continued to knock on the door, but it seemed that their constant pressure would go unrewarded in the first half until Cesc Fabregas drew a rash challenge from Philipp Wollscheid inside the box on 39 minutes, and Hazard fooled Begovic to continue his 100% Premier League record from 18 spot kicks.
However, a moment of magic from Adam cancelled out Chelsea's good work as he collected a layoff from Jonathan Walters to lob Thibaut Courtois from 60 yards with a genuine goal-of-the-season contender.
Stunned by Adam's genius, Jose Mourinho gambled on Costa, who rested his recurring hamstring problem over the international break, but the Spain forward pulled up only 12 minutes after his introduction from the bench.
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They have an in-form replacement in waiting, though, and Remy added to his winner against Hull City a fortnight ago by restoring Chelsea's lead on 62 minutes after being calmly picked out by man-of-the-match Hazard.
Begovic had made good saves from the Belgian and a misdirected Glenn Whelan header to keep Stoke level after the break, but he caught Steven N'Zonzi unawares with a risky clearance which Willian collected to feed Hazard, who beat two defenders and teed up Remy for a simple finish.
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The mid-table Potters came close to a second equaliser when N'Zonzi struck the post with a bending shot which was beyond the reach of Courtois, but the visitors did not seriously threaten again.
Chelsea, who also have a game in hand on second-placed Arsenal, could have settled the game prior to a nervy stoppage time, only for Begovic to produce a strong double save to deny Juan Cuadrado from point-blank range.
Joe Fish
