What United have, and Dortmund lack, is the knowledge that barring a series of bizarre results they will be in next season's Champions' League regardless of the result in this season's semi-final second leg tonight.
United, in beating Liverpool on Saturday, all but confirmed their place as one of the elite eight automatic entrants. Dortmund also played their biggest rivals at the weekend but could only draw at home to Bayern Munich. They now trail Munich by six points with six matches to play. Nor can Dortmund even be sure of reaching the qualifying round as the Bundesliga's second-placed club. They are currently third, three points behind Bayer Leverkusen.
The difference is important for tonight's match will probably be decided by the subsequent reactions of the two sides. Will United, knowing they have a second chance next year, and having got as far as anyone expected this time, be able to relax and play their natural game as they did in thrashing Porto? Or will they lose their edge?
Will Dortmund - who have a number of older players - have their resilience stiffened by the thought that this may be their last chance of glory? Or will that unnerve them?
Dortmund have one other reason to envy United. The German champions, as in the first leg, have much greater injury problems. The talismanic Matthias Sammer, suspended the first time, is injured, as are fellow defenders Julio Cesar, Rene Schneider and Stefan Freund. Jurgen Kohler, who missed the first leg through injury, and the Ghanaian striker, Ibrahim Tanko, were both on the sick list last night and were left in Germany, although they both hope to fly into Manchester this morning. Even if Tanko is fit he will probably start on the bench, as both Karlheinz Riedle and Stephane Chapuisat are fit.
United, having rested four players on Saturday, pick from an almost full squad. Only the suspended Roy Keane is unavailable, and the manager Alex Ferguson's concern is whether to start with Ryan Giggs, fit again, along with David May and Denis Irwin, and retain Ronny Johnsen at the back after his display against Liverpool.
But Dortmund do have something precious which United covet. They have Rene Tretschok's first-leg goal. The goal means Dortmund need only score once to make United score three times. United may have done that against Liverpool but it is hard, though not impossible, to imagine a defence marshalled by Kohler and Stefan Reuter defending as badly as Liverpool did.
So United will have to be careful as they roar forward. One slip at the back and the dream of emulating the 1968 winners is over. But not too careful. "I don't think we'll be good at being really patient, trying to make sure they don't score and worrying about losing a goal," Ferguson said. "There has to be a high degree of concentration and defensive discipline. But there has to be something about our game which reflects Manchester United and the ability of the team.
"We want the level of performance we showed against Porto. We're capable of that. I keep saying to these players 'Reach your capabilities'."
Dortmund are also unlikely to retreat into their shells, despite their advantage. "Our one goal won't be enough," their coach, Ottmar Hitzfeld, said. "We will need to come out and attack and I think we will need one or two more goals to get to the final."
Indeed, both teams are attacking by nature and the Old Trafford pitch is far better than Dortmund's - which affected the quality of the first match. United have the capacity to win but may come to rue the chances they missed a fortnight ago.
Ferguson knows that United have been slow starters in Europe, but believes his young side have learnt valuable lessons. "It's not like going into the torture chamber, it's not that painful," he said. "They start to enjoy it." It remains to be seen whether their enjoyment will last until the final whistle.Reuse content