City made an incredible start with Ilkay Gundogan scoring after 13 seconds, only for Bruno Fernandes to level from the penalty spot after a VAR review. Gundogan hit back once more to claim his brace after the restart and briefly thought he had a third, ruled out for offside, while United went close through Alejandro Garnacho and Scott McTominay but couldn’t find the second equaliser they needed.
Here are the biggest talking points from the derby day showpiece in north London.
Lightning-fast start in record fashion
The fastest-ever goal in an FA Cup final - and what a hit.
Ilkay Gundogan made perfect connection with his volley, running onto the ball to lash it into the top corner and leave David de Gea utterly helpless.
Just 13 seconds on the clock and already a difficult task for United was made monumental - while history was made in the process.
Gundogan went on to net his second with another volley just after half-time and had a would-be hat-trick strike ruled out for offside too - he’ll be a huge loss to City if he does depart in summer.
Garnacho’s impact shows why he’s the future of United
Denied the chance to go to the U20 World Cup with Argentina, Alejandro Garnacho started the afternoon on the bench for United - but when he came on quickly showed why he’s set to play a massive role for the club.
Having recently signed a new long-term contract, that big role is for the long-haul, too.
His first opportunity to run at the City defence ended in a curled shot just wide of the far post, before he teed up a teammate for another chance and almost had another effort on goal himself, blocked at the last after taking on two.
Garnacho’s direct running, speed across the ground and huge levels of self-confidence arguably made him the toughest individual City had to deal with in the heat - even if it was over half an hour rather than any longer.
Erik ten Hag will have seen plenty he likes in terms of planning for next season using Garnacho in a more regular role, but also perhaps something to highlight to the likes of Jadon Sancho, Anthony Martial and Antony: players with high levels of quality themselves but too often dismally lacking in consistency and in impact in the biggest of matches.
Refereeing debates will rumble on
A host of first-half decisions from referee Paul Tierney led to criticism and remonstrations from both sets of players, which is far from unusual admittedly, but a majority of those calls certainly appeared errant in the extreme.
The biggest of the lot was his failure to spot a handball by Jack Grealish, who was jumping to try and intercept a crossfield pass towards Aaron Wan-Bissaka, which after a VAR check led to Man United’s penalty for the equaliser.
Aside from that, though, there was another challenge on Kevin de Bruyne which might have resulted in a penalty but wasn’t given, a yellow card shown to Wan-Bissaka for a tackle which barely scuffed the boot of Grealish, a wild swing from Bernardo Silva on Luke Shaw which should have merited a booking but wasn’t even seen, Casemiro being fortunate to get a free-kick when he clearly committed the foul and should have been booked... and one or two more occurrences besides.
After English referee Anthony Taylor’s performance was criticised in the Europa League final recently - and Jose Mourinho in particular going way too far with his shameful reactions - it would have been hoped that this time around a more competent showing from the officials would be seen.
Too many in red fail to hit top gear
One or two wearing red can certainly be confident they offered as much as possible on the day at Wembley, but for others in Erik ten Hag’s team it was a disappointing day.
Bruno Fernandes gave it his all, Casemiro showed plenty of quality and Shaw was a strong performer, but others who can play a key role just couldn’t get into the game.
Christian Eriksen was one, subbed off around the hour mark after an ineffective showing, while Marcus Rashford being quiet was more down to his team being unable to involve him rather than poor work of his own. Sancho, though, was too often on the periphery and sub Wout Weghorst likewise couldn’t make any impact.
To beat Man City, United needed everyone on point; too many couldn’t hit the heights and that cost them.
Treble bid still on for Pep
Two down, one to go.
City have the domestic double wrapped up with the Premier League and now FA Cup, yet the sense at the club remains the same: the success they want is to conquer Europe.
This will all just be a warm-up to their main event, their real marker which everyone will judge them by, with the Champions League final ahead against Inter Milan.
Pep Guardiola’s team head to Turkey for their final match of the season and the one which will dictate their place in history, be it right at the top as one of the game’s finest, or yet another disappointing footnote despite the trophies which came before.