Southampton - Chelsea's five-match winning streak came to an end in a 1-1 draw at Southampton on Sunday, although the point was enough to keep them at the Premier League summit.
Sadio Mane opened the scoring for the hosts, who impressed in the first half but did little but defend for the second period as Chelsea, who levelled through Eden Hazard just before half-time, launched attack after attack.
Southampton midfielder Morgan Schneiderlin was sent off in the closing stages, but the hosts held on.
The final whistle was greeted joyously by the home fans, who have seen Southampton prosper under new head coach Ronald Koeman, who previously worked alongside Chelsea manager Jose Mourinho at Barcelona.
Chelsea made three changes to the side that beat West Ham United 2-0 at Stamford Bridge on Boxing Day, with Filipe Luis, John Mikel Obi and Andre Schurrle coming in for Cesar Azpilicueta, Willian and Oscar.
Jose Fonte returned from suspension for Southampton, 3-1 winners at Crystal Palace that day, but Ryan Bertrand was ineligible to face his former club and fellow full-back Nathaniel Clyne was unavailable due to injury.
The hosts were fortunate early on when goalkeeper Fraser Forster failed to collect a corner, but John Terry, scorer of the opening goal in Chelsea's two previous matches, could not direct his header on target.
Forster was second to the ball again when Schurrle burst into the box on the left, but the German could only poke wide from a tight angle.
Southampton almost took the lead when Schneiderlin and then Mane connected with a corner, only for Terry to prevent Fonte from tapping in at the back post.
But Chelsea's defence was caught out by the next Saints attack as Mane, put through by Dusan Tadic, kept calm and flicked his shot past goalkeeper Thibaut Courtois as if it were a training exercise.- Fabregas booked for diving -
Chelsea's response was a run from Cesc Fabregas, but Schurrle, right in front of goal, could not get on the end of the former Arsenal captain's deflected cross.
Chelsea levelled in first-half stoppage time when Hazard out-paced Maya Yoshida on the left and cut inside to beat another defender before curling past Forster to convert his side's first shot of the afternoon.
Mourinho made a change at the break, with Willian replacing the ineffective Schurrle.
The newcomer saw two shots blocked in quick succession before referee Anthony Taylor had a decision to make when Fabregas went down in the box under Matthew Targett's challenge.
The official ruled it had been a dive and booked the Spaniard, much to Fabregas's consternation.
Hazard fired across goal and narrowly wide after chesting down a pass as Chelsea began to take control of the game.
Stout defending blocked Diego Costa's shot and he was joined up front by Didier Drogba for the final 15 minutes, with defensive midfielder Mikel the man to make way.
Southampton had hardly threatened all half, such was Chelsea's domination of possession, but the home side continued to defend bravely and in numbers.
They were fortunate, too, with Costa losing his footing in the box after a mis-placed pass from substitute James Ward-Prowse put him in on goal.
The home team had to see out the final two minutes a man down when Schneiderlin, previously booked for a foul on Hazard, hacked Fabregas down and received another yellow card.
This they managed despite Drogba twice threatening to finish off balls into the six-yard box, while Forster had to react sharply after a clearance struck one of his team-mates and rebounded towards him.