In the late-night cafes of the Via Veneto in the city where confirming a miracle is just another day's work, the buzz was that indeed the day had brought something supernatural.
Barcelona had conquered Rome. They had not just beaten Manchester United but played in another dimension, maybe indeed brushed against football eternity.
Lionel Messi, the astonishingly gifted superstar nurtured as a boy with growth hormones, had even jumped higher than towering United defenders to score the killer goal.
The promise of a year earlier in Vienna, where Barca had supplied the core of the team that gave Spain their first major tournament in 44 years, had been fulfilled -- the World Cup in South Africa, duly delivered, would be the underpinning of a football empire which many would soon claim was the greatest in the history of the game.
But is it? We will know a little better at Wembley tomorrow night, but even as Barca's odds shorten to evens -- against United's 12/5 -- there is some reason for caution, especially in the rush to anoint Barcelona as a club without a historic rival.
Graeme Souness, a hard-headed critic if we ever heard one -- and a key figure in a superb Liverpool European-Cup winning team -- leads the acclaim. The Scot swears that not only are Barca the best team he has ever seen but that Messi has outstripped Diego Maradona.
He would have found it hard to pick an argument that night on the terrace of Harry's Bar in Rome, but now surely there must be some murmurings of doubt.
The truth is that if Barcelona are capable of exquisitely rhythmic football, if they have in Messi, Andres Iniesta and Xavi Hernandez an axis of dazzling creativity, they have also fallen some way short of the yardstick they fashioned for themselves two years ago.
Yes, they played a huge part in delivering Spain's World Cup in Johannesburg; yes, they have mopped up La Liga again; but did the Spanish triumph begin to match the sublime authority of Brazil in 1970 or the dynamic impact of Maradona 16 years later in Mexico City? Hardly.
Spain scored eight goals, 11 less than Pele's Brazil, despite playing one game more, and six less than Argentina.
In Rome, the fact that United had scarcely begun to play was discounted briskly enough. The picture painted was exclusively in the hues of the new champions of football, the team whose influence would touch every corner of the game.
Yet within the year Jose Mourinho was successfully parking a bus manned by an Internazionale team who would prove quickly enough incapable of reproducing such powers of destruction.
It is also true that if Barca have returned to the peak of European football to re-state their case as the nonpareils of the ages, they have lost at least some of the lustre handed to them so quickly.
They have yet to match the ascendancy of some of their champion predecessors including Liverpool, Ajax, Bayern Munich, Milan and Real Madrid.
In the semi-final legs against Mourinho's Real, Barcelona won through with bursts of sublime football, but not before a descent into some of the grubbiest gamesmanship seen even in this age of institutionalised cheating.
Of course there is all-time glory in the work of Pep Guardiola, the coach who has created the truly miraculous image of a football man who believes in the beauty of football for its own sake.
But the idea that his team is both unmatchable and immaculately conceived has received some not inconsiderable buffeting since their victory in Rome.
Inter barred the road to last season's Madrid final and on the way drew from Sergio Busquets a piece of cheating that is still hard to dislodge from the memory.
This time, against an Arsenal side largely outplayed and reduced to 10 men after Robin van Persie saw red, they made it through only because Nicklas Bendtner missed a simple chance in the last moments.
These are not the credentials of a team of the ages, one of authority and composure and striking ability which many would attribute more readily to the Milan of Franco Baresi, Paolo Maldini, Frank Rijkaard, Ruud Gullit and Marco van Basten.
There is the suggestion that some of the highest hopes surrounding Barcelona after that warm night in Rome have yet to be fulfilled.
It might well be that Messi and his friends will impale the doubters at Wembley; that United are heading into a firestorm of brilliance.
The point here, though, is that Barca carry the burden of proving their greatness. United merely have to do something that is plainly still within their powers; to compete in such a way that we know can frustrate and make anxious their hugely exalted opponents.
It happened to Barca, after all, the last time they were in London, when they were beaten 2-1 by Arsenal. A fine team of beautiful talent, it is easy to say. But are they unbeatable?
The record and instinct says no. For United, certainly, it is reasonable to imagine that something less than a miracle might just do.