Chelsea made it eight consecutive wins in the Premier League as they came from behind to keep their place at the top of the table with a 3-1 victory over title rivals Manchester City, who were reduced to nine men in the dying moments at the Etihad Stadium.
An own goal from Gary Cahill in the first half had put City in the lead and on course to go top, but Chelsea fought back after the break with strikes from Diego Costa, Willian and Eden Hazard to send them four points clear at the summit. City were reduced to nine men deep into second-half injury time after Sergio Aguero and Fernandinho were both sent off.
The game started off as a tense and tight affair with the first real sight of goal only coming after 15 minutes when Hazard fizzed a first-time hit from the edge of the area just wide of the post.
City had their first real effort six minutes later, with Aguero seeing a strike from just outside the box tipped over the bar by Thibaut Courtois.
City soon had the ball in the back of the net when Fernandinho headed Kevin De Bruyne's free kick past Courtois, but the flag had already gone up for offside on the Brazilian.
Moments later, Chelsea were attacking down the other end as Hazard latched onto a through ball before rounding Claudio Bravo, but instead of attempting to finish into the back of the net from a tight angle, he cut the ball back across goal with City's defence able to clear the danger.
City could well have been reduced to 10 men in the 30th minute after David Luiz appeared to barge over Aguero as the last man and with the Argentine seemingly through on goal, but referee Anthony Taylor waved play on.
The hosts upped their tempo as the first half wore on and Aguero had a goal-bound strike blocked by Cesar Azpilicueta after Leroy Sane had teed him up, before the striker later spurned an even greater chance after heading De Bruyne's delivery wide of the target when in a great position.
But City's pressure was finally rewarded on the stroke of half-time when Jesus Navas' cross from the right was diverted into the far corner of the net by Cahill to gift his opponents the lead.
City started the second half brightly and almost doubled their advantage as Sane drove forward towards the Chelsea box before slipping in De Bruyne, but the Belgian was unable to slot the ball past Courtois.
Chelsea fashioned a half-chance a few seconds later when Victor Moses fed the ball to Costa, but the striker could only fire wide from distance.
City soon had two great opportunities within a matter of minutes to double their lead, but Aguero's shot was cleared off the line by Cahill after he had cut out Marcos Alonso's poor backpass, before De Bruyne then smashed the bar from just yards out with an empty net in front of him following Aguero's ball across the face of the goal.
The hosts were made to pay for their profligacy in the 59th minute when Chelsea found an equaliser, with Costa latching onto a Cesc Fabregas pass before turning Nicolas Otamendi and firing past Bravo for his 11th Premier League goal of the season.
And a breathless period continued when City created an excellent opportunity to restore their lead, but Aguero was denied by Courtois after he had been played in by De Bruyne.
It was Chelsea, however, who soon found the lead on 70 minutes, breaking clear on a counterattack as Costa played the ball into the path of substitute Willian, who rifled the ball into the bottom corner past a stranded Bravo.
City brought on Yaya Toure and Kelechi Iheanacho in an attempt to haul themselves back into the game but despite some late pressure from the hosts, Chelsea were able to break away and score a third at the death as Hazard raced clear of the defence before slotting past Bravo.
Things went from bad to worse for City deep into stoppage time when Aguero was sent off for a wild lunge on Luiz, with Fernandinho then also shown a red card for grabbing Fabregas round the neck and shoving him over an advertising board.
The defeat for City means Pep Guardiola's side have still not won at home in the league since Sept. 17.