Jesse Lingard will learn from his mistake which gifted Young Boys a famous 2-1 Champions League win over Manchester United, says Ole Gunnar Solskjaer.
United, who had Aaron Wan-Bissaka sent off, looked set to hang on for a point in Group F in Switzerland.
But a poor back pass by Lingard, who had replaced Cristiano Ronaldo, allowed Jordan Siebatcheu to score the winner.
"We're humans, every footballer makes mistakes," said United boss Solskjaer.
Ronaldo had given United the perfect start against the Swiss champions with his third goal in two games since re-signing from Juventus.
However, right-back Wan-Bissaka was shown a straight red card before half-time for a lunging tackle on Christopher Martins.
Moumi Ngamaleu equalised before Lingard's injury-time error left United reflecting on a seventh defeat in 11 Champions League matches under Solskjaer.
"With Jesse, no footballer likes making mistakes but it's obviously part and parcel of the game," added Solskjaer, whose side managed just two shots during the game against a team that had to qualify for the group stage.
"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."
'Lingard not to blame'
Lingard, 28, enjoyed a productive loan spell at West Ham last season, scoring nine times in 16 Premier League games.
He has rejected a contract offer at United and his current deal runs out at the end of the season.
United captain Harry Maguire said Lingard was not to blame for the defeat which leaves United with an uphill battle in a group containing Spanish side Villarreal and Italian side Atalanta, who drew 2-2 in Spain.
Cristiano Ronaldo scores for Manchester United against Young Boys in the Champions League
United host Villarreal at Old Trafford in their next group game on September 29, a repeat of last season's Europa League final which Solskjaer's team lost on penalties.
"I'm sure everyone on that pitch today has made a mistake. I'm sure Jesse will pick himself up," added Maguire.
"It's the first game in the group. We've got many games to bounce back and we must do. We'll try and pick up three points in our next game and build momentum from there."
'Aaron is one of the best in the world'
Wan-Bissaka's red card changed the dynamics as United gradually lost momentum.
United missed out on qualifying for the knockout stage in last season's Champions League after losing three of their six group matches.
"You need 10, maybe 12, points, you need to win your home games, win one away from home," added Solskjaer.
Aaron Wan-Bissaka is shown a straight red card during Manchester United's Champions League defeat to Young Boys
"Of course we've lost the opportunity to get three points but we've got two home games next and got to focus on them two.
"Lack of concentration, make a mistake and you get punished. You get done. We did that last year in Europe.
"Today in the last seconds Jesse just wants to play it safe and just one misplaced pass and you've conceded a goal.
"Aaron's normally a very, very astute tackler - one of the best in the world.
"We know we've given ourselves a more difficult task than what we did last year but everyone thought we were through after two games last year."
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