Via Veneto, it was necessary to remember here yesterday, is not the kind of street which comes so easily to a standstill. It did once, it is true, when a lorry driver crashed his airbrakes when he spotted Sophia Loren (but not the cameras) as she acted out her role as a lady of the night – and then returned to his cab sheepishly after failed negotiations.
But then Loren is Loren and who would have thought that a rather plain little fellow who only rose to 5ft 7in with the help of growth hormones might one day have a similar impact. It happened, though, yesterday when Lionel Messi, surrounded by carabinieri, checked into the Grand Hotel.
It just went to show that after all the years of being worldly wise the old thoroughfare is still susceptible to an injection of high-grade glamour.
Messi's kind may never be transferred to celluloid but it was real enough when his name swept down the pavement cafes. The resulting crowd spilt into the sunlit street and put the police and security guards under considerable pressure.
What kind of glamour precisely? It is that which comes with astonishing accomplishment and the promise of unforgettable deeds, and if you don't happen to be utterly committed to the cause of Manchester United it is impossible not to grasp the sense that the great anticipation of the Eternal City is for a performance from the little man to transcend the normal expectations placed on a single player in a single game.
For a parallel you probably need to go back 23 years to that time when Messi's latest mentor, Diego Maradona, strode with the demeanour of a fighting cock down the smartest streets of Mexico City on the eve of Argentina's World Cup final with West Germany.
Maradona revelled in the attention of the world – and he delivered and, now nearly a quarter century on, the same question is being asked of another diminutive Argentine. Can Messi indeed prove exceptional to a degree that will be indelible down the years? Can he deliver as Maradona did? Can he make the best efforts of Manchester United seem as futile as those of Lothar Matthäus, the German master craftsman who was assigned to shadow genius in the Azteca Stadium and found it as elusive as a gust of wind?
A little bit of every football fan, whatever his allegiance, wants it be so. He or she wants to see the ransacking brilliance of the little man on a flood tide in the Stadio Olimpico, however underwhelmed he might have been by the statement from Messi that he and his Barça team-mates have already established their right to put their hands on the greatest trophy in the club game.
But then who will store up indignation if Messi proves as good as his word, if he outstrips the Adonis, Cristiano Ronaldo, if he does with wit and mesmerising acuity what his Portuguese rival to the title of the world's greatest footballer does with an imperious surge and ball-striking which can render feeble so much of happens around him?
Not many, you can be sure, because there is nothing quite like the sight of an ultimate player to blur the old boundaries of partisanship.
Manchester United, who so many times have been carried on tides of romance and affection which had as their origins emotions which were as much about an idea as a reality, can hardly complain if Barcelona are guaranteed the most passionate support in the big and beautifully set stadium beside the Tiber. It is odd yet indisputable that it is not United but Barça who represent the romance tonight, who promise the greater capacity to make beauty on the football field.
Sir Alex Ferguson will certainly not bemoan the development as he juggles with the strategic possibilities of leaving such talent as Dimitar Berbatov and the force of Carlos Tevez on the bench while Park Ji-sung and Anderson and Wayne Rooney run ferociously to push back the brimming creativity of such as Messi, Andres Iniesta and Xavi Hernandez.
The suspicion here is that United will sooner or later rejoice in their new casting as the hard and practical men. To reach this conclusion you do not have to draw out some elaborate form line. You just have to recall how perilously Barça lived at Stamford Bridge in the semi-final a few weeks ago, how seriously they were arrested by the power and the application organised by Guus Hiddink, a work of stifling so close to complete that not only was Messi reduced to the rag ends of his brilliance, Iniesta was directing the team's first shot at goal in stoppage time when he conjured the goal that carried him here.
And then you think of United's dismantling of Arsenal in the same round, admittedly with a little help from fate early on, but in the end with a certainty that so cruelly laid bare Arsène Wenger's belief that his young, and defensively inadequate, team had indeed found some of the unity and the innate brilliance of the greater sides he had before. After seeing that, and then the way Chelsea hounded Barça in a way that could have brought only one result but for the hapless work of the referee, the magic of Messi and his team-mates could never be quite so persuasive this side of tonight's kick-off.
Of course the magic lingers. Iniesta extended its shelf life for at least a few weeks and, who knows, it may be that the returning Thierry Henry, who this season has proved more than once that he is not altogether spent up in the alchemy department, may seize the chance to banish the horrors that came to him in the Stade de France three years ago. If ever a player of great talent had the stage, and the moment, to fulfil himself it was surely Henry for Arsenal against Barcelona in 2006, Henry slipping clear of the cover and with the goal at this mercy, and Henry doing the unthinkable, snatching at an opportunity made for his silky assassin's hand.
Henry may restore himself tonight as a European Cup final performer, he may put away the memory of how his time of all times was ravaged by the brilliant intervention of another veteran, Henrik Larsson.
Messi may take back for himself the distinction that was wrestled, sometimes literally so, away from him at Stamford Bridge. He may announce that the people who kicked over the café chairs in the Via Veneto yesterday were right to see more than a time-expired messiah of football.
It is, no doubt, the most intoxicating possibility of the Roman night. But there are other images and they will not go away. They have a Rooney or a Ronaldo or maybe that other Argentine, Tevez, burrowing beyond the weakest point of Barcelona, the defence which buckled so hazardously at Stamford Bridge. It is of Manchester United, of all people, saying, enough of the beautiful game and the beautiful Barcelona, this is the time for strength and for a little of that cold and cutting steel which in the end generally separates the winners from the merely romantic.
The wider football world may well yearn for Barça tonight. But the gut instinct says United, maybe by as much as 3-1.
Road to Rome: How United and Barça made it this far
Neville landmark 17 September
United kicked off the defence of their title with a goalless draw against Villarreal, a game more notable for club captain Gary Neville playing his 100th Champions League match. He joined the likes of Thierry Henry, Raul and Paolo Maldini – as well as team-mates Ryan Giggs and Paul Scholes – in the 100 club.
Dimi up and running 30 September
After a season of yearning for a move to Old Trafford from Tottenham, Dimitar Berbatov had secured his £30m move. After a quiet start to his United career, the Bulgarian opened his account against Aalborg, notching twice in the second half of a 3-0 win – the second a classy volley to finish off the Danes.
Messi at the last 1 October
Trailing 1-0 at Shakhtar Donetsk in the final minutes, Barça relied on Lionel Messi for inspiration, the Argentine conjuring two late goals to spare the Catalans' blushes. Tapping in from a goalkeeping error, Messi levelled the tie before coolly curling a finish into the far corner in added time to keep the Spaniards' campaign on track.
Barça show depth 22 October
Thierry Henry, Samuel Eto'o and Andres Iniesta were left on the bench as Josep Guardiola rotated his squad for the trip to Basle. Bojan Krkic took advantage, the 18-year-old scoring twice in a superb display, missing out on a hat-trick when lobbing over the bar. Messi grabbed his third goal in two games to secure a 5-0 win.
United break record 24 February
A goalless draw at Internazionale in the second round sees United set a Champions League record of 20 games without defeat. The run surpasses a record previously held by Ajax and Bayern Munich, both in the 1970s. The Reds' last defeat remains the 3-0 semi-final loss at Milan in April 2007 – now 25 matches ago.
Thierry triumphs 24 February
Thierry Henry showed Barcelona supporters why the club shelled out £16m to bring the former Arsenal captain to Spain, the Frenchman scoring the equaliser in an exhilarating match of free-flowing football. Lyons led through a Juninho free-kick before Henry stooped at the far post to head home the leveller.
Special One silenced 11 March
Memories of Jose Mourinho's exuberant celebrations down the Old Trafford touchline in 2004 were banished as United followed up their away draw at Internazionale in the first leg with a 2-0 stroll. Nemanja Vidic and Cristiano Ronaldo scored to silence the former Chelsea coach and send United through.
Magical Messi 11 March
Messi helped secure Barça's passage into the last eight as the Catalans overcame Lyons 5-2. Hugging the right touchline, the maestro controlled a long ball on his chest before cutting inside and leaving four players in his wake. Taking the ball on his left foot, he angled a shot into the corner. One of the goals of the season.
Portuguese pain 7 April
A straightforward quarter-final tie at home to Porto turned into anything but for United. The Portuguese side went a goal up through Cristian Rodriguez before Wayne Rooney and Carlos Tevez appeared to have given Alex Ferguson's side a first-leg advantage, only for a late strike from Mariano to restore parity.
Bayern battered 8 April
After a 12-1 aggregate win over Sporting, Barça were expected to be pushed harder by Bayern in the last eight, but the Germans were destroyed in a scintillating first half. Messi, Henry and Samuel Eto'o ripped them to shreds, with Henry's smooth finish the pick of the Barça strikes.
Rocket Ronnie 15 April
Goal of the tournament? Of the season? You'd be hard pushed to find a better strike than Ronaldo's 40-yard strike at Porto in the quarter-final second leg. Trailing on away goals, the Portuguese midfielder picked up the ball just inside the Porto half, took a touch, then unleashed an unstoppable effort into the top left corner.
Cech mate 28 April
The total football of Barcelona met the brick wall of Chelsea at the Nou Camp, Petr Cech keeping the score goalless almost single-handedly in this semi-final. Eto'o came closest, Cech deflecting his shot wide when one-on-one, before Dani Alves saw his drive tipped over. Several penalty claims were also refused.
Gunners fire blanks 5 May
Expecting an epic tussle in the semi-final against Arsène Wenger's aristocrats, United instead crushed a poor Arsenal outfit at the Emirates. The only sour note was Darren Fletcher making a rash challenge on Cesc Fabregas, the Scot receiving his marching orders, ruling him out of the final.
Iniesta at the last 6 May
The pre-match hype surrounded Leo Messi but it was Andres Iniesta who came to the rescue with a 93rd-minute effort to break Chelsea hearts. Repeated penalty claims waved away by Tom Henning Ovrebo caused several Blues players to surround the referee, Michael Ballack and Didier Drogba the worst culprits.
