Chelsea increased their lead over second place Manchester City to six points but were held 1-1 by a well organised Southampton side this afternoon at Stamford Bridge.
The Blues took the lead on 11 minutes through a Diego Costa header but a Dusan Tadic penalty, 10 minutes later, gave the visitors something to fight for.
Chelsea were terrible in the opening 45 minutes, a hangover from their Champions League exertions maybe.
But after the restart, they were reenergised, just a shame they came up against an inspired Fraser Forster who made a least six key saves.
A fine counter-attack by the Blues on three minutes which involved five players saw Chelsea cut the visitors apart. But the ball fell to Cesar Azpilicutea, on the left, who lost his composure and shot the ball high over Fraser Forster's goal
But the determination to break the resistance of Southampton bore fruit on the 11 minute when Eden Hazard fed the ball wide to Branislav Ivanovic. The Serbia defender send in a first-time cross and Diego Costa rose, unchallenged in the six-yard box to header powerfully home past Forster. It was the Brazil-born spain striker's first goal for Chelsea since January 17 against Swansea.
The Saints almost equalised immediately but Thibaut Courtois parried away Sadio Mane's close-range effort.
But they got their reward on 18 minutes when Nemanja Matic needlessly hauled down Mane in the area and referee Mike Dean awarded Saints a penalty. Dusan Tadic rammed the ball down the middle of the goal, Courtois's trailing leg got a touch to the ball but not enough to save the visitors' going level.
Chelsea had a case for a penalty when Ivanovic went down in the Saints's area - Tadic did tread on his left heel, but Dean probably thought Ivanovic's theatrics disguised a dive and played on instead.
Tadic forced a save from Courtois on 30 minutes after easily cutting through the Chelsea rearguard.
A sensational save by Courtois opened the second half from a blistering Toby Alderweireld 20-yard free kick.
Out of sorts Matic was replaced by Ramires eight minutes after the restart. Chelsea started to pile on the pressure and Costa was unlucky not to have score but he saw his clipped shot bounce off the upright after Willian hit in a low drive into the penalty area.
With 18 minutes left, Forster produced a brilliant double save, the first to thwart Oscar's point-blank header from six yards out, the second to stop Hazard's near post followup shot.
The keeper was in action seconds later, this time kicking away Oscar's left-footed effort.
That was his last action of the game as Jose Mourinho replaced him with striker Loic Remy. This was quickly followed by Cuardrado, on for a limping Willian.
Azpilicueta almost won it for the Blues at the death but Forster, again saved at his near post. Forster then stopped a Remy drive while a double effort from John Terry failed to pierce the Saints defence.
Chelsea's next game is a trip up North to visit Hull City on Sunday.
Teams Chelsea, Courtois, Ivanovic, Fabregas, Oscar, Hazard, Costa, Matic, Willian, Cahill, Terry, Azpilicueta
Subs, Cech, Luis, Zouma, Ramires, Drogba, Remy, Cuardrado
Southampton, Forster, Clyne, Schneiderlin, Fonte, Long, Davis, Mane, Tadic,Wanyama,
Alderweireld , Bertrand
Subs, Davis, Yoshida, Gardos, Djuricic, Ward-Prowse, Pelle, Targett.
Referee Mike Dean