For Sir Alex Ferguson it is back to the Nou Camp for the first time since the miracle of 1999: Barcelona, how could we forget?
Nine years on since his greatest moment as manager of Manchester United, Ferguson must look at his latest generation of players and think that if this team cannot win the club's third European Cup then perhaps he will never lay his hands on it again.
Carlos Tevez's goal 20 minutes from time was the difference last night but it was not the second half that will concern Frank Rijkaard and the boys from Catalonia. It was in the first 20 minutes that United showed the devastating style which has earnt them the title of bookmakers' favourites for the Champions League title. In that time their passing and their running demolished the Roma defence and they did it with a team that did not even include Wayne Rooney or Cristiano Ronaldo.
This is Ferguson's fifth time in the semi-finals of the Champions League and with a 2-0 lead over Roma at the beginning of the night he was confident enough to field a team without Rooney, Ronaldo or Paul Scholes. Despite a missed penalty from Roma, his belief in the less-celebrated members of his squad was vindicated, especially in a towering performance from Owen Hargreaves and more of the same from others such as Michael Carrick, Anderson and Tevez.
United are the third English side in the Champions League semi-finals – just as there were three in last year's final four, a competition that ended rather less gloriously for the Premier League with Milan winning. It would be more of an achievement for English football if there were more Englishmen in these three teams but it is certainly a reflection of the wealth of the Premier League. The final in Moscow on 21 May is all that really matters and if Liverpool and United are there, the mind boggles at how the fans will be kept apart by a police force not known for their sensitive approach to law and order.
From the directors' box, Eric Cantona looked down with quiet satisfaction upon the kind of football this United team can play when they cut loose. The Frenchman is, of course, regarded as the father of the modern United style but not even his great teams of the 1990s could turn it on like this bunch. Any side that can convert Hargreaves from a conservative holding midfielder into a rampaging winger-cum-centre-forward in one night are certainly worth watching.
Hargreaves played like a man undergoing some kind of identity crisis: goodbye to that life of humdrum tackling and 10-yard passes; hello to goal-scoring opportunities and devil-may-care forward runs. Particularly at the start of the game he popped up all over the pitch, running on to through-balls down the centre or flying down the right wing. It was his exquisite cross from the right that Tevez stooped to head past the Roma goalkeeper, Doni, and put the Italians out of their misery.
Without Ronaldo and Rooney – the latter played the last 16 minutes – there is still a very decent attacking force in United's squad. For the last 10 years Ferguson has tried to convince himself that, within reason, he can afford to leave out his star players for games when the job in hand is not so daunting. As he said later, Ferguson "has to believe in his squad" and they gave him reason to do so last night. More pertinently he has given a rest to two major players ahead of Sunday's visit from Arsenal, who have been afforded one extra day of rest.
The Barcelona side that Ferguson's men will face in the first leg at the Nou Camp on 23 April is not quite the all-conquering team that swept to the title in Paris against Arsenal two years ago. Ronaldinho is injured for the rest of the season and the team is second in La Liga, six points behind Real Madrid with seven games left to play. But there is still plenty to occupy Ferguson in the form of Lionel Messi, Thierry Henry, Samuel Eto'o and Bojan Krkic, the latest prodigy to step off the production line.
There was a spirit about United in the early stages that seemed to say that, playing this way, they could miss as many chances as they wanted – a goal would surely come sooner or later. A defence that included Mikael Silvëstre, playing for the first time since 15 September, and Gerard Pique were little more than interested bystanders as United swept forward.
It was easy to forget that United had not taken the lead as each chance came and went without being converted. Daniele De Rossi had forced Edwin van der Sar into a save on 13 minutes but serious trouble did not find the United goalkeeper until just before the half hour. Then Mancini tried to wriggle past Wes Brown in the left channel of the area and the defender went to ground and made his tackle; a heartbeat later the Brazilian lurched forward and on to the floor.
It was a difficult call for the Norwegian referee Tom Henning Ovrebo. Brown seemed to play the ball but some replays suggested he had connected with Mancini's foot, which had in turn struck the ball. On the touchline Ferguson waved his arms about and shouted at the fourth official. In the end he need not have worried: with Old Trafford on tenterhooks, De Rossi blasted his penalty into the Stretford End.
Tevez's goal was immaculately worked and exactly the kind of strike that United had threatened so many times in the first 20 minutes. Tevez won the ball in the midfield, twisted clear of his markers and spread the ball wide to Hargreaves on the right. He surged forward and then struck a wonderful out-swinging cross that Tevez, diving at the near post, directed across Doni and into the far corner.
In the closing stages Gary Neville got a first run-out since 17 March last year and Ferguson told Ronaldo to sit back down on the bench. Ronaldo was not even born when United beat Diego Maradona's Barcelona 3-0 in March 1984 in the European Cup-Winners' Cup quarter-finals, on one of Old Trafford's greatest European nights. At least, this time, United will be able to say the best player in the world is on their side.
Manchester United (4-1-4-1): Van der Sar; Brown, Pique, Ferdinand, Silvestre; Hargreaves; Park, Carrick (O'Shea, 74), Anderson (Neville, 81), Giggs (Rooney, 74); Tevez. Substitutes not used: Kuszczak (gk), Ronaldo, Scholes, Welbeck.
Roma (4-2-3-1): Doni; Panucci, Mexes, Juan, Cassetti (Tonetto, 56); De Rossi, Pizarro (Giuly, 67); Taddei (Esposito, 81), Perrotta, Mancini; Vucinic. Substitutes not used: Curci (gk), Cicinho, Aquilani, Brighi.
Referee: T Ovrebo (Norway).