Chelsea 1-1 Southampton
A third draw in four home games still put Chelsea six points clear at the top of the Premier League.
Blues came back from a gutting exit in the Champions League to start slowly and finish like a train.
Unfortunately, a well-drilled Southampton made sure the Jose Mourinho express was shunted into a siding, at least for the time being, but no one would bet against the league winning ticket ending up in SW6.
A frantic last few seconds saw Chelsea stab and thrust goalward, with John Terry somehow missing by a matter of feet after terrific saves from Fraser Forster.
For all that, Blues were ahead through, who else, but Diego Costa.
The hotshot's 19th goal of the season was brilliant counter attack, but it needed a pinpoint centre from Branislav Ivanonvic to allow the Spaniard to head back across goal and beyond Forster.
A minute later it could have been level. Sadio Mane squandered a great chance although Tibault Courtois got down well to thwart the Saints striker for all of eight minutes.
The keeper nearly got to the equalising penalty from Dusan Tadic, when he sent his spot-kick went straight down the middle with Courtois getting a toe end to it.
There was more on Mane from Nemanja Matic to give away the penalty in the first place. But in the ongoing debate between what constitutes a decent tackle and a foul, the Blues midfielder lost out to referee Mike Dean. It looked hard on Chelsea, but although Costa sent another header just wide, the opposition grew into the game.
The hitman thought he had won a penalty on 55 minutes, but Dean keen to award one the other way in the first half, was having none of it.
Costa hit the frame seconds later with a left-foot stab from corner as chaos reigned in the Saints penalty area, but in a game of even Steven, Tadic weaved a magical path into the Blues box only to get stopped at the last.
Forster came to Southampton's rescue on 72 minutes, not once but twice in the space of a second.
The keeper with the most clean sheets in the Premier League got lucky to be in the right place to stop Oscar's header, and then blocked the follow up from Cesc Fabregas.
Oscar was next to test Forster, but again the keeper did well to come off his line, spread his 6ft 7ins frame, and thwart Chelsea.
He did the same at the end from Terry, but it's a point closer - and at this stage of the season it's money in the bank.
Blues: Courtois, Ivanovic, Cahill, Terry, Azpilicueta, Matic (Ramires 53), Fabregas, Willian (Cuadrado 83), Oscar (Remy 82), Hazard, Costa; subs not used: Cech, Filipe Luis, Zouma, Drogba,
Referee: Mike Dean