A healthy victory over Internazionale is the preferred option but United will be careful not to let the Italians leave Manchester with a goal that might count double at San Siro in two weeks' time.
"A win is vital," Roy Keane, the United captain, said, "but we don't want to concede any goals. Italian teams are very good at coming to places and nicking that precious away goal. Then they go home and concentrate on finishing you off there.
"It's important we blank them out because we are capable of scoring against the best in the world. We've proved that in Europe this season."
Keane was an injured and uncomfortable spectator at the corresponding stage of the European Cup last season when United secured a 0-0 draw in Monaco but were felled by David Trezeguet's seventh-minute goal. Ole Gunnar Solskjaer managed an equaliser but United were unable to put their noses in front.
The feeling within the United camp is that they are stronger now and better equipped to cope in Europe. "We're not afraid of any team, anywhere," Keane added. "We know all the Inter players because most of them were in the World Cup. Like anybody they have strengths and weaknesses."
Keane played only 45 minutes against Southampton on Saturday, scoring United's opening goal in a 2-1 win and his presence will be highly valued by his manager, Alex Ferguson, who believed the Irishman's injury last season was the prime reason why United won nothing.
"We have to improve on our performance against Southampton," Keane said. "We said after that match that if we play like that on Wednesday we'll be on our way out of the Champions' League."
Like Keane, Ryan Giggs was also injured against Monaco and like his captain the Welsh winger was unequivocally upbeat yesterday, pointing to the pounds 27.5m paid out in the summer for Jesper Blomqvist, Jaap Stam and Dwight Yorke as a reason why.
"The boss spent a lot of money but he has bought quality," Giggs said. "It's added to the strength of the whole squad, which we need when we are going for something like the European Cup. We're as well equipped as we can be to win it now. Last year when we had injuries we struggled, but not this time.
"There's a hunger at Manchester United and the European Cup is the competition that drives us on. It's a long time since the club won it last, so there is pressure. Just like when we hadn't won the League for so many years. But we won the League and we know that if we can beat Inter we've got a great chance in Europe this season."
United's chance tomorrow will be enhanced by a full squad to choose from. Stam, who missed the Southampton game, has recovered from a hamstring strain and the only slight doubt is Phil Neville, who injured a knee on Saturday.