Chelsea's Diego Costa in action with Southampton's Nathaniel Clyne (Photo: Reuters)
Chelsea opened up a six-point lead at the top of the Premier League despite being held to a 1-1 draw against top-four hopefuls Southampton in an absorbing game at Stamford Bridge on Sunday.
Diego Costa opened the scoring for Chelsea in the 11th minute with a close-range header but Southampton deservedly equalised eight minutes later through Dusan Tadic's fortuitous penalty.
Southampton dominated for much of the opening period but Chelsea asserted their authority after the break with Costa clipping the post while John Terry was denied in a frantic finish.
Chelsea lead second-placed Manchester City, who were beaten 1-0 by struggling Burnley on Saturday, with a game in hand while Southampton are sixth, three points behind fourth-placed Manchester United.
United host fellow Champions League qualification hopefuls Tottenham Hotspur and Newcastle United travel to Everton later on Sunday.
"We deserved the points because we had a lot of chances," Tadic told Sky Sports.
"In the end we had a little bit of luck but we played really good and we showed that when we play like a good team nobody can beat us."
Chelsea needed 11 minutes to open the scoring when Costa capitalised on inexplicably static defending from Southampton, who boast the league's meanest defence, to head home Branislav Ivanovic's accurate cross.
The visitors offered an instant reminder of the threat they pose when Sadio Mane drew a stunning reflex save from Thibaut Courtois before Tadic curled an effort over the bar.
Minutes later, however, Mane was felled by Nemanja Matic in the area and Tadic converted from the penalty spot, although his tame effort was fortunate to beat the trailing feet of Courtois.
With parity restored, Southampton's fluid, pacy attacking trio of Tadic, Mane and Shane Long were able to carve out a host of opportunities against Chelsea's rattled defence.
A marauding Ivanovic burst into the Southampton area in the 29th minute and went to ground after contact from Tadic but referee Mike Dean waved away the appeals despite the Serbian's dramatic fall.
Courtois, Chelsea's busiest player during the opening period, was again called into action to deny Tadic and Mane while, at the other end, Costa went close again with a header.
Toby Alderweireld's rasping free kick after halftime was beaten away by Courtois, but Chelsea were then able to reassert their authority.
Costa guided Willian's rasping shot against the post while Fraser Forster brilliantly repelled Oscar and Hazard.
In a frantic finish Loic Remy drew a superb save from Forster while Terry was denied by a desperate challenge from the rebound before lashing a second effort wide.
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