Edin Dzeko comes off the bench to score his first Premier League goal — one that could prove pivotal in City's hopes of gaining a Champions League place.
A momentous win for Man City's Champions League dream
Blackburn Rovers 0 // Manchester City 1
Yet the consequences of last night's win at Ewood Park may even outstrip the potential gains of their Wembley Stadium victory.
With a four-point lead over the fifth-placed Tottenham Hotspur and just five matches remaining, fourth position - and a place in the Champions League - is theirs to lose. Indeed, with Arsenal in reverse gear, third might be there for the taking.
Moreover, it was a triumph that came with a welcome benefit: just when it seemed City were missing Carlos Tevez, their hamstrung captain, Edin Dzeko compensated with his first Premier League goal to determine the outcome.
It amounted to a clinical, professional performance from City. There is a sense that Roberto Mancini's preferred brand of football is professional and controlled, with as few alarms as possible.
This was a match to tick most of the boxes, decided by an intervention from the bench. With a stalemate beckoning, the City manager removed Adam Johnson and introduced Dzeko. Three minutes later, the newcomer made the breakthrough.
In one respect, it was a fortunate goal - the outstanding Phil Jones intercepted David Silva's cross, only for the ball to fall to Dzeko to drive it in - but in another, it was a fitting outcome. Close to his elusive, exhilarating best, Silva was the outstanding player on show.
He had threatened to orchestrate a rout from the first whistle. City were assured in possession and fluent in their movement. In the third minute, it almost brought a breakthrough.
Pablo Zabaleta's cross looped up off Gareth Barry to fall invitingly for Silva. With a sweet swing of his left foot, the Spaniard volleyed against the near post, a motionless Paul Robinson beaten.
A theme was developing. The goalkeeper was defeated again a quarter of an hour later. Saved by the woodwork initially, his second rescue act was a teammate.
Michel Salgado, on sentry duty on the goalline, cleared Barry's header away after the midfielder met Aleksandar Kolarov's corner.
Robinson was belatedly exerted after the interval, stretching to tip over Yaya Toure's header after Silva found the Ivorian with a deftly-weighted cross. The match-winner against Manchester United was in similarly buccaneering form, striding purposefully into Rovers territory on a succession of raids. Wandering infield with deceptive menace, Silva later whipped a shot just past the post. He is more comfortable as supplier than scorer, however, and Dzeko's winner goes down as another goal he has fashioned.
Blackburn, meanwhile, drew a blank for the third time in four matches.
Save for a somewhat optimistic penalty appeal from Jason Roberts and a header that his partner in attack, Benjani, directed some way wide, they barely threatened in the opening exchanges. Then, however, they were roused by the youngest player in the team.
A 50-yard solo run from the teenage defender Jones, a wonderful demonstration of his potential, galvanised the crowd and spurred his colleagues on.
Christopher Samba, his fellow centre-back, came close with a looping header that dropped just past Joe Hart's far post.
But City weathered the predictable aerial attack and Dzeko compounded Blackburn's problems. Without a win in three months, they have fallen from seventh to 16th. City should savour this win, not least because they might not be returning to Ewood Park for quite some time.