Frank Lampard's late penalty earned Chelsea victory and condemned leaders Manchester City to their first Premier League defeat of the season.
Lampard - once again excluded from Chelsea's starting line-up by manager Andre Villas-Boas - came off the bench to score the winner with seven minutes left after Joleon Lescott handled Daniel Sturridge's shot.
Mario Balotelli gave City a lead their early domination deserved but Chelsea forced their way back into contention through Raul Meireles's equaliser before half-time.
Roberto Mancini's side were reduced to 10 men early in the second half when Gael Clichy was sent off, leaving Chelsea to make the most of their numerical advantage and record a third win in succession to leave City with a two-point lead over neighbours Manchester United at the top of the table.
City will regret not putting the game out of reach in an imperious opening spell - but Chelsea demonstrated the resilience of old to survive that siege and emerge with a win that puts them only seven points off the Premier League summit.
Villas-Boas insisted Chelsea were showing signs of a revival after beating Newcastle United and Valencia following a torrid spell. This, however, was a serious examination of their recovery and they passed the test successfully.
And Lampard, pushed to the margins in the last two games, proved his character to step up under pressure in the closing minutes to convert that vital penalty. Villas-Boas revealed afterwards that Juan Mata had been the designated spot-kick taker, but after a brief discussion with the Spaniard Lampard took responsibility.
City's unbeaten league run came to an end after 15 games - now Mancini and his players must regroup ahead of Sunday's meeting with improving Arsenal at Etihad Stadium.
Chelsea made one enforced change, with Jose Bosingwa replacing the suspended David Luiz - while Balotelli was recalled to instant effect for City.
Sergio Aguero must take much of the credit with a turn that left John Terry trailing and a sublime pass with the outside of his right foot into the path of Balotelli. The young Italian may be turbulent elsewhere, but in the penalty area he is calmness personified, as he proved by dismissing the attentions of Branislav Ivanovic to round Petr Cech to score.
City were in command and should have doubled their lead after 14 minutes when Aguero brushed aside Bosingwa and wrong-footed Ashley Cole, only to drag his shot wastefully wide.
David Silva then appealed for a penalty when he fell under Bosingwa's challenge - but referee Mark Clattenburg waved play on while declining to punish the Spaniard for diving.
Chelsea, as much by force of will as any real superiority, dragged themselves into a game which had been completely in City's control and were rewarded with an equaliser 11 minutes before the break. Once again the goal owed almost as much to the creation as the finish, with the impressive Sturridge escaping from the toiling Clichy before crossing for the incoming Meireles to volley powerfully past City keeper Joe Hart.
Former Manchester City player Sturridge was one of Chelsea's leading lights on a stormy evening and he was only just off target with a rising drive a minute after the restart from Mata's free-kick.
City went down to 10 men just before the hour when Clichy, who had been booked early in the second half for fouling Sturridge, tripped Ramires to earn his second yellow card. It capped a miserable night for the defender, who had suffered in the face of Sturridge's pace and threat.
Chelsea, having been outplayed in the early stages, now sensed victory and Villas-Boas introduced Lampard with 17 minutes left in an attempt to make their numbers count.
Mancini appeared to have settled for a point by removing Aguero for Kolo Toure and sending on Nigel de Jong for Silva - but Chelsea were not to be denied.
And Lampard it was who put Chelsea in front with seven minutes left. There were few complaints from City after Sturridge's shot hit the raised hand of Lescott - leaving Lampard to drill the penalty straight down the middle before celebrating with the supporters behind the goal in the Matthew Harding Stand.