Manchester United will become the first team to go through the Champions League group stage without conceding a goal if they can keep a clean sheet at home to free-scoring Valencia on Tuesday.

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 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," he added.

While the gamble to experiment has paid off in the Champions League, a youthful United side came crashing down to earth last week when the holders lost 4-0 to West Ham United in the League Cup to end a 29-match unbeaten run in all competitions.

Six clubs currently hold the record for the fewest number of goals conceded in the Champions League group stage. Ajax Amsterdam, Chelsea, Juventus (twice), Liverpool, AC Milan and Villarreal share the honour with one goal.

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.

They were, however, boosted by news goalkeeper Cesar Sanchez had been included in the squad for the trip to northwest England. The first-choice keeper has been sidelined since last month with a calf injury but trained with the team on Sunday.

Valencia, fifth in La Liga, travel to watertight United with one of the most potent strike forces, having scored 14 times in their five Champions League matches.