Former Manchester United goalkeeper Raimond van der Gouw is concerned David De Gea's lack of experience could be a factor this season.
De Gea looked confident on United's pre-season US tour, but he and manager Sir Alex Ferguson know the real test will come when the champions begin the defence of their league title at West Brom next weekend.
"De Gea looks a good all-round goalkeeper," former United keeper Van der Gouw told the Sunday Express. "But 20 is a very young age to be playing for Man United."
Van der Gouw, now coaching in his native Holland, spent six seasons at Old Trafford as understudy to Peter Schmeichel and Fabien Barthez.