A last resort, yes, but prodigal son makes killing contribution

There were times last night when Carlos Tevez seemed less a moral dilemma for Manchester City manager Roberto Mancini than a last resort – and so it was right to the moment his team came back into the Premier League title race with an authority that smacked of, well, champions.

If we want a pecking order of merit in the revival that may well have rescued City's season from appalling anti-climax we should perhaps give the honour to Samir Nasri, the man who conjured the winning goal and played throughout with an impressive desire to shape events. Not so far behind was Sergio Aguero, who nervelessly struck home the equalising penalty and played, as always, with an abiding passion.

But then, irrepressibly, there was Tevez, producing a moment of chemistry and insight which will always mark out those who come to life in that place where it matters.

He was the perfect foil for Nasri as Chelsea – a plainly revived Chelsea – were finally put down.

The prodigal son Tevez, who in less complicated days made a habit of scoring against Chelsea, was as subdued as you might have expected when he took his place on the bench. It wasn't long, however, before his demeanour became decidedly more perky.

Indeed, as City's opening surge ebbed with the disappointment of Nasri's strike against the crossbar and Mario Balotelli's squandering of a gift casually donated by, of all people, Frank Lampard, Tevez might have imagined the roasting of a fatted calf.

City needed the kind of momentum Tevez once supplied as a matter of routine, which is of course something quite separate from the argument that the crime he perpetrated in Munich last autumn should really have put him beyond the consideration of all but the most desperate of managers.

Unfortunately for a City title campaign which rippled with such confidence and invention so recently, that was the category Mancini placed himself in from the moment City's early conviction has started to fade.

Mancini's body language became progressively bleak. Several times his frustration was directed at the languid Balotelli and it was no great surprise when the big, unfathomable man was withdrawn from the action at half-time.

Less predictable, as Tevez inched forward in his seat, was the Italian's replacement, the recently disaffected Gareth Barry. The purpose of this, it was clear soon enough, was to allow Yaya Touré to move more freely into advanced positions. Such gathering concern turned to outright crisis when the best Touré could do was get the deflection on a shot from Gary Cahill that slipped by Joe Hart.

Inevitably, Tevez came on to cheers. Yet it was that other Argentine, the one whose commitment has never been in question in any circumstances who suggested most strongly that he might drag City back into a race which Cahill's goal could so easily have stopped dead. Aguero ran with ambition and when Michael Essien handled the ball at point-blank range it was he who stepped up to the penalty spot with a matador's composure. His equaliser was sure.

In view of his earlier disappointments, it was maybe fitting that Nasri should supply the killing stroke. And, as inevitably as his appearance at some point in the action, it was Tevez who made a killing contribution.

The Frenchman played the ball into the box and there was Tevez to play a quite exquisite reverse pass to Nasri. City were alive again that was reason for celebration enough. Should Tevez even have been on the field? The argument was suspended in at least half of the football city – and certainly in the final statement of Roberto Mancini's body. He reached for the sky and said that morality could wait.