This was massive. The pride of Manchester - though 200 miles removed, was at stake. One half was an old stager here, with Wembley as a second home. The other has visited just twice since the night Ricky Villa danced through their defence. Both expect to be back again sooner rather than later. City will be first, as they return to their first FA Cup final since 1981. United will need to beat Schalke over two legs to be in the Champions League final.
Talk of a Treble is finished, and the boys of '99 can stay on the pantheon. Few could argue that this set of Red Devils possesses the class of those fabled predecessors. With the sending off of one of that number, Paul Scholes, United were left to emulate the team of 2008. A Premier League-Champions League double will have to do, though it is hardly a given. Schalke, Barcelona, Real Madrid and Arsenal can all take heart from City's ending of a dream here.
The victors can enjoy their own much deserved glory day. Roberto Mancini has his Mel Machin moment, and this was far sweeter than Maine Road in September 1989. Forget 5-1, 1-0 was enough for City and a path to silverware and the scrapping of that mocking ticker at Old Trafford can be scheduled. Thirty-five-and-a-bit years can come to an end on May 14, and all that money will seem worth it. Saturday night will be a good, good night for them, though their manager did his best to keep his feet and expectations on the ground. They still have a final to play, and this is a club which has made its reputation in snatching comedic defeat from expected victory.
"I am very happy, and I am very happy for our supporters," said a smiley Mancini. "They deserve a day like this afternoon. But we must not forget that we should play another game."
City had begun nervously, their unfamiliarity with this venue perhaps weighing heavy as United were first to settle. The first 25 minutes were coloured red but fortunes swung on two chances that evaded a man who once turned down City in favour of United.
He is often accused of looking like he does not care, but the pain wracked on Dimitar Berbatov's face looked real enough. First, Joe Hart saved at point-blank range, with 15 minutes played. Barely a minute later came a miss from just yards out that saw the Bulgarian agonise and seek answers from the heavens. It had been from a similar angle to that which Javier Hernandez had scored against Chelsea on Tuesday. That time, the net billowed. This time, the ball boys were called into play.
Wayne Rooney's suspension meant he watched the game attired in the questionable sartorial choice of shirt, ties, shoes and tracksuit top but United missed the remodelled Rooney that has flourished of late. As against Everton two years ago when an indolent penalty cost United a place in the final of 2009, Wembley provided significant ammunition to Berbatov doubters. His late removal in favour of Anderson saw him slink off in resignation, his veneer of detached calm replaced by a pained look of a man who feels he has let the side down.
His equivalent in engimatism is Mario Balotelli, an Italian with a gift for hi-jinks and headlines. A lack of Carlos Tevez meant he would be City's main man. And it was he that produced City's best effort of a first half. A thunderous volley forced Edwin Van der Sar, almost twice Balotelli's age, into a fine reflex save. A driving run from distance also forced an opportunity that saw Vincent Kompany narrowly miss from 25 yards as half-time beckoned. Balotelli had lifted his team-mates, and they had a foundation to build on. The second period was theirs by right. Though he would engage in a childish spat with Rio Ferdinand in the game's immediate aftermath, an incident with which Mancini played the Wenger card of not seeing it, the faith that his compatriot has placed in the striker was rewarded. Edin Dzeko served as a £27 million benchwarmer, the suspicion growing that like many of Mancini's charges, he was not the choice of the manager.
Mancini has been accused of lacking the ability to motivate a team unbalanced by the riches splashed on it, but whatever was said at half-time, after which City arrived fully three minutes later than United, must have been inspired. "All the players were very emotional," said Mancini. "We knew that we could play better and we can win this game."
Their efforts and belief were soon granted a deserved goal. Loose play from Michael Carrick saw Yaya Toure presented with the opportunity to make a surging run to the heart of United's defence that ended with a crisp finish. From there, City dominated the anaemia of Monday night at Anfield replaced with vigour and creativity. Once Scholes had committed a studs-up challenge for which any amount of apology could not hide its recklessness, City were able to enjoy their day. Only a Nani free-kick that Joe Hart was forced to tip on to the bar registered as a decent chance for United.
Rooney's foul mouth at Upton Park now looks costly. Continuing resentment of that FA punishment was perhaps a leading factor in Sir Alex Ferguson's choice of remaining silent after this game. If he had spoken, he could have offered little in the way of excuses. His team could not recreate the drive and creative edge that has recently been in evidence. Vincent Kompany, a true leader, marshalled a fine rearguard effort though a lack of ideas was also in evidence for United. Javier Hernandez missed his usual partner once he came on for Valencia, and was left to chase shadows in listless circles as a pipe-dream faded.
Manchester City, for the first time since May 1981, a month in which Bobby Sands and Peter Sutcliffe were the headline-makers, can now believe that their painful drought is at its end.
MAN OF THE MATCH: Yaya Toure His wages are astronomical but he is now propelled into the stratospheric heights of City legend with his winning goal from an opportunistic strike. Previously his fitness has been in question but he did his best to cover every blade of Wembley grass for 95 minutes of play. In fact, his drive was just what United had lacked throughout.
MANCHESTER CITY VERDICT: Now you're gonna believe them. Whomever of Stoke City or Bolton Wanderers have an opponent to fear. They rode their luck but deserved it too. Their spine of Hart, Kompany, Toure and Balotelli all excelled and they were comfortable once they were faced with ten men and had the lead.
MANCHESTER UNITED VERDICT: They began with an aristocratic air but faded fast. Nani's creativity was lost amid his propensity for the dark side of his personality, while Scholes' sending off was both rash and indicative of a player whose end is near. Can anyone say that this team possesses the class of its antecedents? A chance at Treble glory always looked beyond their remit.