Having taken so long to get here, nobody wanted to leave. Brighton’s players and staff lapped the pitch long after full-time, grins wider than their faces, and soaked up the joy of a crowd whose exhortations had palpably been laden with extra passion and meaning throughout. This was a night that lifted the soul and stirred the heart; goodness knows there have been few of them over the past year but the home team and returning fanbase raised one another to create an occasion whose mark on this stadium’s history will be indelible.

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In football terms this was a dead rubber but the atmosphere resembled that of a knife-edge affair, a play-off match perhaps. It survived disappointments like a goal from Ilkay Gündogan when the game had barely kicked off, and temporarily lapsed into polite applause when Phil Foden scored a magical solo effort to put Manchester City two ahead and seemingly guarantee the champions three points.

But Brighton, a man up from João Cancelo’s 10th-minute dismissal, kept coming and turned the scoreline around to create a din befitting an audience many times bigger than the 7,945 present.

“It’s been a tough year and a bit,” Graham Potter said. “We’ve suffered a lot. ‘Emotional’ is a good word to describe the feeling in the stadium and I thought the players gave everything, they gave a really top performance.”

Their efforts were crowned by a winner from the least predictable of sources. Dan Burn had not scored in 68 games for Brighton but, by the time Leandro Trossard slipped him through inside the box, they had levelled things up and anything seemed possible. The centre-back in Burn reared its head as he almost lost his footing before seeing Ederson save his first effort; he was sharp enough to squeeze in the rebound, though, and it was bedlam in the stands. “I don’t rule anything out with Dan, he’s that kind of character and that kind of player,” Potter said.

Earlier in the game there had seemed to be little on the table for Brighton, though. The crowd had playfully booed City’s early touches but, when Riyad Mahrez took possession for the first time, he shifted the ball on to his left foot and supplied a precise cross for Gündogan to nod across Robert Sánchez on the run.

Gündogan would take an almighty clattering from Alireza Jahanbakhsh later in the first half, which brought a booking for the home forward and visible discomfort for one of City’s most valuable players. He was replaced early in the second half but Pep Guardiola suggested his medical staff were “quite optimistic” that nothing is amiss with the Champions League final looming.

That might have been Guardiola’s only concern had Cancelo not erred soon after the opener. Cancelo misjudged the flight of a volleyed, backspinning long pass from Alexis MacAllister and grappled with Danny Welbeck, who would have been through if perhaps not in full control of the ball, as the forward ran past. The appeals from all sides of the ground were raucous and it was tempting to wonder whether Stuart Attwell would have brandished his red card, a decision upheld by VAR, as quickly if the external pressure had been at behind-closed-doors levels.

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“I didn’t see it,” Guardiola claimed. “We’ll have to improve for the final, we always have to finish with 11 players.” Being shorn of Cancelo meant any plans for City to limber up quietly for Porto went askew; instead they found themselves embroiled in an intense, heady skirmish that mirrored its environment.

Foden appeared to have settled it on his own shortly after the interval when, after taking possession ahead of Ben White and shrugging him off over a blistering 60-yard run, he finished clinically. Any supporter watching Foden in the flesh would feel lucky, but he was quickly upstaged. Trossard had replaced the luckless Welbeck, seemingly hamstrung, during the first half, and seized on a Rodri error before driving into the penalty area. He took the long route to goal, cutting from left to right before feinting and finishing emphatically, raising the roof.

That had little on the reaction when Adam Webster, hanging in the air to thud Pascal Gross’s cross past Ederson, equalised with 18 minutes left.

Then Burn arrived from nowhere and even the normally mild-mannered Potter forgot himself, sparking disquiet on the City bench.

“I was a bit emotional, it wasn’t my finest hour, I apologise to them,” he said. But this was an evening on which anyone could be forgiven for letting off steam.