After securing just one point from the opening two matches in Group A, the Blues finally chalked up a win in the competition and at the same time left Villarreal scraping bottom of the table and seemingly fatally holed.
But it took a disputed injury time winner - the Spaniards protested long and loud that it was offisde - from Sergio Aguero to seal a first ever win in Europe’s premier club competition.
Indeed it wasn’t plain sailing from the off for the Blues who fell behind to Ruben Cani’s prodded fourth minute goal after an initial shot was beaten away by Joe Hart.
It was a shock to the system for a team not used to finding itself behind but the response was encouraging with Nigel De Jong and Samir Nasri only just off target and Aleks Kolarov bringing a fine save from Diego Lopez via a free kick.
An equaliser was always on the cards and it came in the shadow of the half time interval courtesy of an unlikely source, Carlos Marchena the Villarreal defender, who turned the ball into his own net under pressure from Edin Dzeko.
The second half was one of nothing but frustration as Dzeko missed two presentable chances one with his foot and the other with his head and all looked less than rosy when Pablo Zabaleta’s 90th minute header was saved by Lopez.
But cometh the hour; cometh the man and top scorer Aguero changed the mood and sent 42,000 people wild when he slid home Zabaleta’s cross just as the referee looked ready to blow.
There wasn’t the vitality or verve of recent wins but this was every bit as sweet as City ground it out against a side that has never failed to the progress from the group stage of a European tournament.
As is his way on these occasions and with a nod to the weekend trip across town, the wily Italian strategist at the helm of the Blues made multiple changes to the side that swept England’s Villa aside at the weekend.
Goal-happy Mario Balotelli wasn’t available as he finished serving a three-match ban imposed for on the field indiscretions at the end of last term but back came Edin Dzeko who hadn’t started a match for City since the last outing in this competition.
Leading marksman and scoring hero Aguero started from the bench as he eased back from a groin strain that Mancini was clearly not keen to aggravate before the derby.
The full backs went through the rotating door with Gael Clichy and Micah Richards ushered to the side lines in favour of Alex Kolarov, scorer of the Blues only Champions League goal before this contest and Pablo Zabaleta who couldn’t even find a place on the bench at the weekend. Kolarov was superb as an attacking force.
In, too, from the start came David Silva and Samir Nasri but the intricate passing and movement of the Blues mini-marvels was never too much for the Spaniards who had already lost to both Munich and Napoli in their opening assignments but were asked by their coach to be brave – and they were.
Those previous reverses meant that Villarreal couldn’t come looking for a draw and their willingness to counter-attack meant the game was pleasing on the eye and devoid of the cat and mouse that often typifies the opening halves of Champions League games.
Even so the yellow-shirted visitors, who are nicknamed the Yellow Submarine, were regularly in damage control mode, filtering behind the ball and making it hard to find space where they could. Ultimately, however they were no more successful at the ploy than a string of beaten domestic opponents.
Four points from three games is perhaps not what Roberto Mancini would have predicted or wanted but six from the last three ought to be good enough to secure safe passage into the knockout phases. That quest begins in the return game with Villarreal early next month.
City fans on Twitter voted Aleks Kolarov as their man of the match for a great attacking and defensive performance.
