Ole Gunnar Solskjaer said his young players lack the know-how to win in certain situations after watching Manchester United come from two goals down to draw 3-3 with Sheffield United.
Goals from 19-year-old Brandon Williams, 18-year-old Mason Greenwood and 22-year-old Marcus Rashford turned the game on its head at Bramall Lane as United briefly led, but that did not stop Solskjaer from condemning his side's first-half performance.
Defeat against the Blades would have heaped pressure on manager Solskjaer, who has delivered just two wins from United's last eight Premier League matches, and the former striker sensed a lack of confidence among his players.
"In football, you've got to earn the right to win the game and we didn't have any right to win the game after 70 minutes," Solskjaer told reporters.
"The boys are young and it's not a lack of desire; it's maybe that confidence in themselves. Andreas [Pereira] and Fred in midfield have never played together before, but the way we came out after [Sheffield United] scored the second was excellent.
"I don't doubt [the players] wanting to win but sometimes young players don't know how to win challenges like this and we must have learned a lot today."
United's travel to Kazakhstan to face Astana in the Europa League on Thursday before their Premier League campaign resumes at home against Aston Villa on Sunday, and Solskjaer said he hoped the comeback at Bramall Lane would have a positive effect on the mentality of his squad.
Sitting in ninth place in the Premier League table after 13 games has left United open to criticism, but they have only lost two of their last 12 games in all competitions and Solskjaer pointed to an improvement in team spirit this season.
He said: "When you're 2-0 down and don't give up, you don't expect them to give up, but last year we did and this year we didn't, so it's a massive, massive difference in that respect.
"To do something about it and I think the way they've turned it around, it changes so much in young players' heads.
"You remember these boys are young, and when they get the belief after the first goal, Dan James - probably the first time he went past [Enda] Stevens - and put a great cross in, fantastic finish by Brandon [Williams] - suddenly you see we're on the front foot and the boys are trying things that lead the fear away.
"Now, [my thoughts are] positive, even though the big part of this game is very negative and you're disappointed with it, but that's football for you and to have the character to stick in there."