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 – especially when you remembered his emphatic pre-match statement that his men had both the competitive character and the right to sweep on to the club's first title since 1968. 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his frustration was directed at the languid Balotelli and it was no great surprise when the big, unfathomable man was withdrawn from the action at half-time.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. Certainly City needed such force with rapidly increasing urgency – and then to the point of salvation in a wavering cause.
Such gathering concern turned to outright crisis when the best Yaya Touré could do was get the faintest deflection on a shot from Gary Cahill that slipped by Joe Hart.
Inevitably, Tevez came on to the most unambiguous cheers. They signalled not so much forgiveness as a very basic demand for the kind of atonement which was once his stock in trade, eruptions of will in the most critical areas of the field.
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 Gary Cahill's goal could so easily have stopped dead.
Aguero ran with trademarked force and 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. The equaliser was sure and it told us that City may just have found again the touch and the belief that had made them so dominant for so much of the season.
Mancini had cried out for a restatement of such character and now all that earlier despair was cast away by one of those goals which separate the thoroughbreds from the triers.
In view of his earlier disappointments, it was maybe fitting that Nasri should supply the killing swordstroke. And, as inevitably as his appearance at some point in the action, it was Tevez who made a killing contribution.
The Frenchman, who had seemed so intent on making an impact that hadn't always been so apparent at crucial stages of the season, played the ball into the box and there was Tevez, the striving redemption man, to play a quite exquisite reverse pass to Nasri.
City were alive again and for a little while at least 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.