Their tight defence in European games has been in contrast to erratic domestic performances at the back and has often been down to promising displays by some of their younger players, who look likely to be given the responsibility once again.
United and Valencia have already qualified for the knockout round although top spot in Group C is still up for grabs. The English club, who have 13 points from five games, will win the group if they do not lose to the Spaniards, who are on 10.
With United facing important Premier League matches against leaders Arsenal and champions Chelsea in the next fortnight, manager Sir Alex Ferguson's policy of giving his youngsters a run-around in Europe looks set to continue.
"We have some fantastic young players at the back," 31-year-old Wes Brown, whose place in defence has sometimes been taken by the new crop, told the club magazine Inside United.
"You could play a good back five with some of them in there; Ben Amos in goal, Rafael at right-back, Jonny Evans and Chris Smalling in the centre and Fabio at left-back. That is the next generation."
United got some extra rest this week as Saturday's league game at Blackpool was postponed because of a frozen pitch, while Valencia's preparations have been less than ideal.
They are still smarting from Saturday's 2-0 defeat at Real Madrid when a harsh second yellow card for midfielder David Albelda left them with a man less for the last 25 minutes.
Up to then they had held Jose Mourinho's side, causing them problems by crowding the midfield and breaking quickly. The extra space worked in Cristiano Ronaldo's favour and the former Manchester United forward scored twice in the closing stages.
