Ole Gunnar Solskjaer believes Jesse Lingard will learn from his error that handed Young Boys a stunning 2-1 Champions League victory over Manchester United.
The English side appeared to be clinging to a point in Group F in Switzerland after Aaron Wan-Bissaka was sent off, but Jordan Siebatcheu scored the game-winning goal when Lingard, who had replaced Cristiano Ronaldo, made a terrible back pass.
"We're humans, every footballer makes mistakes," said United boss Solskjaer.
With his third goal in two games since re-signing from Juventus, Ronaldo had given United the perfect start against the Swiss champions, but right-back Wan-Bissaka received a straight red card for a lunging tackle on Christopher Martins just before halftime.
Moumi Ngamaleu equalized before Lingard's injury-time blunder handed Man United their seventh Champions League defeat under Solskjaer.
"With Jesse, no footballer likes making mistakes but it's obviously part and parcel of the game," added Solskjaer.
"We'll learn from it, he'll learn from it. He'll pick himself up and be ready to go on Sunday against West Ham. Today in the last seconds Jesse just wants to play it safe and just one misplaced pass and you've conceded a goal."
28-year-old Lingard had a productive loan spell with West Ham last season, scoring nine Premier League goals in 16 games, and he has now turned down a contract offer from United, with his current contract expires at the end of the 2021/22 season.