For Manchester City, there will be other nights of glory and no doubt many more chances to seal the ultimate prize that has eluded them once again this season.
But for their visitors, and ultimately their conquerors, Tottenham Hotspur, this felt like a once-in-a-generation opportunity.
Spurs lost 4-3 on the night but reached the last four of the Champions League for the first time courtesy of the away goals rule.
The first leg, defined by Hugo Lloris' penalty save and Son Heung-min's second-half goal, almost seem a lifetime away now.
Perhaps that's the way it should be, nobody quite remembering the details amid the chaos of one of the finest spectacles European football has ever produced.
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Yet for Pep Guardiola and everyone associated with City, the second leg at the Etihad will be remembered for all the wrong reasons.
Fernando Llorente's goal, which ultimately proved decisive, appeared to graze the striker's arm on the way in off his thigh.
The thing about VAR is that it doesn't solve such disputes once and for all. It only adds to the drama and it wasn't done there with the tie poised in Spurs' favour at 4-4 on aggregate.
Mauricio Pochettino's men absorbed everything the English champions threw at them, right up until the 93rd-minute when Raheem Sterling breached their defences for his hat-trick.
The Etihad erupted, Guardiola raced down the touchline, and all the indications were that City would be meeting Ajax in a fortnight's time.
Instead, the VAR check judged Aguero to have been offside in the build-up.
It would have been priceless to see Christian Eriksen's reaction, the Dane at fault for giving the ball away instead of clearing his lines.
What was captured on camera, though, was Guardiola's response. Just moments after the commentator described Lloris as "crest-fallen", that was exactly how the Catalan looked.
Here was his initial celebration:
Those scenes quickly turned to the City boss dropping to his knees and putting his head in his hands:
The agony and the ecstasy of football summed up perfectly.
City have little time to lick their wounds either as they quickly turn their attention to retaining the Premier League title.
They'll do so on Saturday lunchtime against none other than Tottenham.News Now - Sport News