After 52 years of the European Cup in its various formats, it comes as a shock to realise that Manchester United and Barcelona, two of the world's most glamorous clubs, have been crowned champions no more than twice apiece. In United's case, there were 31 long years between the triumphs at Wembley in 1968 and the Nou Camp in 1999, but the Catalans' wait for even a first success seemed endless, and was made all the more painful by the way in which their rivals Real Madrid dominated the competition.
Sir Alex Ferguson remembers going to Wembley for Barcelona's eventual triumph in the 1992 final against Sampdoria and thinking the match programme must be mistaken in suggesting that they had never yet won the trophy. Even then, it took another 14 years to add a second win, in fortuitous circumstances against Arsenal.
Meetings with United have usually throbbed with goals, which adds to the sense of anticipation surrounding Wed-nesday's semi-final first leg in Spain. The 3-0 victory over Diego Maradona's side in 1984 to overcome a 2-0 deficit was one of the great Old Trafford nights, of which the hero, Bryan Robson, said: "I've never heard a noise like it." United's 1991 European Cup-Winners' Cup final success was a landmark for the whole of English football, as a triumphant and peaceful return to European competition after a five-year ban, and also confirmed that Ferguson was reviving the club as a serious force.
A heavy Nou Camp defeat followed in 1994, when handicapped by the "five foreigners" rule; then two thrilling 3-3 draws in the group section of the Treble season before a surreal climax at the same venue against Bayern Munich. Ryan Giggs was one of those who learnt from the 4-0 drubbing: "It was an experience," he said. "We were understrength and they had great players like Koeman, Romario, Stoichkov. You learn more from defeats than the wins and there were a lot of young players in our team that night. Barcelona away, you get beaten 4-0, you've got to grow up quick. And you realised if you don't perform against these big teams on the big stage you'll get a doing."
A new generation were taught the same lesson in a bitterly disappointing defeat by Milan in last year's semi-finals. Now Cristiano Ronaldo, Wayne Rooney and the rest have the chance to make their mark against a Barcelona side who cannot, like United, hope for a domestic championship as a consolation if things go wrong. "Our form has been more consistent than Barcelona's but that's not to confuse the issue of it being a big game," Ferguson said on Friday. "Barcelona's players will respond to the occasion and they have players who can change a game, we're aware of that. If all my players are fit, I think we have a good chance but you don't take semi-finals against Barcelona for granted. With their history, the way they play, and the wide pitch, there are a lot of advantages for Barcelona in this game."
Plenty of width can hardly be a handicap for United, especiallyif Ronaldo and Giggs are allowed to play down the flanks. At 34, Giggs has accepted that being "rested" means exactly that, and he admits to benefiting: "I've adjusted. You've got to realise that you're older and you prepare that little bit differently. You don't play in every game and you do a bit more training and just make sure you're ready when the manager does pick you.
"When you play every game, like I was a few seasons ago, it's play-rest-play-rest and it's all about recovery. I don't get disappointed when I'm not on the teamsheet because I'm experienced enough to know I'll play enough games and that if I'm playing well, I'll play in the big games. You've got to be sensible.The manager's looking at the bigger picture, and we have a lot of players to choose from."
The depth of that squad has been one of the keys to United's success this season, and Ferguson's rotation has attracted less criticism than that of other managers largely because he has stronger understudies to bring in. His eyes light up, too, at the cosmopolitan nature of the squad: "I see them all sitting at the table and I've got Spanish, Argen-tinians, Brazilians, Portuguese, French, Serbians and they're all communicating and laughing with each other, and you say to yourself, 'Why don't they understand me?' They're going,'Carlos, Carlos, what does the boss say'?"
The Glaswegian accent, unrefined by 21 years in Manchester, nevertheless manages to get the message across eventually. There will come a time, of course, when it is necessary to move on, and Ferguson is particularly keen to ensure the eventual handover is smoother than the disastrous transition after Sir Matt Busby's departure, with United contriving to be relegated within six years of winning that first European Cup.
Sadly for their rivals, there is no suggestion that even a third one in Moscow next month would prompt an abdication.
Watch Manchester United's visit to the Nou Camp on Wednesday on Sky Sports 2, kick-off 7.45