Kobbie Mainoo and the box-to-box run that won Manchester United the FA Cup | OneFootball

Twenty seconds before he scores the most important goal of his young career, Kobbie Mainoo is in his own penalty area hassling Kevin De Bruyne. The ball pinballs into the air, Mainoo heads it on to Bruno Fernandes, and then he starts running.

Stuck in a corridor of City players, Fernandes does what most Manchester United players now do when down a dead end, and looks for Mainoo. Mainoo is expecting the pass and already knows what he’s going to do with it: he takes a touch before rolling it with the outside of his foot to Marcus Rashford on the halfway line, and keeps on running.

Rashford sweeps the ball to Alejandro Garnacho surging down the opposite flank, Garnacho squares to Fernandes, who plays a deft flick to Mainoo arriving in the box. Kyle Walker is chasing but all he gets is the best view in Wembley of Mainoo’s side-footed finish past a diving Stefan Ortega.

If Erik ten Hag could have drawn up a counter-attacking goal on his dressing-room whiteboard, this would have been it, flowing from one end to the other, never more than a couple of touches, always moving, always knowing the next pass before it’s played. And if a manager could dream up a box-to-box midfielder they would look something like Mainoo, a player with endless energy, with a freakishly calm head and an uncanny knack for escapology.

The FA Cup final was not meant to be this way. The giant pitch was meant to suit Manchester City and help them monopolise the ball. United were supposed to huff and puff and ultimately blow out in the summer heat. Instead City played without their usual pep and United capitalised, exploiting the open spaces behind City’s vulnerably high defence.

And the heartbeat of this victory was Mainoo, producing an all-round midfield display that should be taught in academies. His defensive work might need some finesse, evidenced late in the first half when he snapped through the back of Kevin De Bruyne and was booked. But his man-marking job meant every run was tracked and attempt to find space closed off, and it was so effective that De Bruyne was subbed off with less than an hour played.

Alejandro Garnacho and Kobbie Mainoo scored United’s winning goals (John Walton/PA Wire)

Mainoo is hugged by teammate Christian Eriksen after full-time (AFP via Getty Images)

On the ball, Mainoo danced through gaps and pirouetted away from potential tacklers, gone before they understood. He knitted and stitched around City’s midfield, always precise and concise. At one point in the first half he span behind Rodri with a one-two and then effortlessly dragged the ball away from a closing Mateo Kovacic to safety. In a congested midfield containing De Bruyne, Rodri and often Phil Foden too, the most impactful player was their 19-year-old opponent.

Mainoo is already resembling the complete midfield player, someone who can hold when required but who can influence in the final third too. His next match will be in an England shirt, most probably one of the two warm-up games before Euro 2024, and there is no doubting his place in the final squad; the question now is whether he should start the opening group game alongside Declan Rice and Jude Bellingham in midfield. He would be the junior partner but you suspect it wouldn’t show.

With 10 minutes to go, the ball ran off the pitch for a throw-in and Mainoo’s midfield teammate Sofyan Amrabat walked over to give him a cuddle of appreciation. In the final throes Mainoo was still going, carrying the ball out from his own half before releasing Rasmus Hojlund on the counter-attack. After he passed, he kept on running.

When the full-time whistle went, he sank to his knees. He celebrated with Garnacho, two years after they won the FA Youth Cup together as skinny academy players – watch back videos of that game and it is striking how much Mainoo has grown physically since then, although his graceful game looks identical. “I’ve played my way through the academy and I’ve not changed for the occasion,” he said recently. “If you do get nervous, you start to change.”

Finally, he left the pitch wearing a red bucket hat and an FA Cup winner’s medal around his neck.

“In a final, anything can happen,” Mainoo had said this week. “We are not coming to take part, we are coming to win. We have players who can lead the team.” No one noticed it at the time, but Mainoo was talking about himself.