Carlos Tevez made an immediate impact on his return to Manchester City as the Argentine set up the winning goal in his team's crucial 2-1 victory over Chelsea on Wednesday.
A goal from Gary Cahill had appeared set to end City's streak of 19 consecutive home league victories but, with the hosts trailing 1-0, Roberto Mancini introduced Tevez, back with the team after his six-month exile, as a 66th minute substitute.
The controversial Argentinian was greeted by a smattering of boos from home supporters.
But, within 12 minutes of his arrival, those jeers had been silenced and City were level as Michael Essien handled a Pablo Zabaleta shot and Sergio Aguero equalised with a superbly-struck penalty.
It set the stage for a fascinating finale and, with five minutes remaining, Samir Nasri played a short ball to Tevez, who returned the pass on the edge of the area for Nasri to calmly convert the winning goal.
The victory means City move to within one point of leaders Manchester United having played the same amount of games as their bitter rivals.
Mancini's men are also only the fourth team ever -- and the first in Premier League history -- to record 20 consecutive home wins in the top flight.
If City were low on confidence, as some had suggested in the wake of exiting the Europa League and falling four points behind United in the Premier League, their opening to the game did little to suggest that.
After a minute, a David Silva corner was headed out to full-back Zabaleta whose shot, from the edge of the area, was deflected behind.
A mistake by Ashley Cole then presented the ball to Zabaleta who pulled it back for Silva, who leant back to shoot over disappointingly from just inside the box.
There was a quick, and almost lethal, response from Chelsea as Fernando Torres darted towards goal before squaring to allow Mata a shot which the midfielder placed well wide of the City goal.
Considering the stakes, there was little caution on display from either side and, after eight minutes, Yaya Toure's well-judged through ball was controlled superbly by Nasri, on his chest, before the winger volleyed over Petr Cech and saw his effort strike the cross-bar and rebound to safety.
Frank Lampard's woeful short pass on the halfway line just before the half-hour was collected easily by Mario Balotelli who outpaced the Chelsea defence but shot well wide of the mark, with Cech getting the slightest touch.
A Zabaleta cross was met by a bicycle kick from Aguero which failed to trouble Cech, a sign that chances were becoming fewer as the half drew to a close.
Mancini took off the ineffective Balotelli, to be replaced by Barry at the interval with Aguero and Nasri now spearheading the frontline.
City's best attack to that point came after 55 minutes when Nasri's chip across goal struck the cross-bar and was kept in play by Zabaleta whose near-post cross was back-heeled into the side netting by Silva, via a touch from Lampard.
Chelsea opened the scoring on the hour in controversial fashion after David Luiz and Gareth Barry tangled as they competed for a half-cleared Juan Mata corner.
While City appealed for a foul, Cahill played on and his shot took an unkind deflection off the boot of Yaya Toure, wrong-footing Joe Hart on its way into the City goal.
City's response was to bring on Tevez for the final 25 minutes of a game which they simply could not afford to lose.
It was an inspired move. City levelled through Aguero's 78th minute penalty and the home team dominated the remainder of the game before Tevez's astute pass set up Nasri for a dramatic 85th minute winner.