Manchester United boss Jose Mourinho has explained why he sometimes has doubts about young players.

Citing Marcus Rashford's mentality, Mourinho admits others struggle with his demands.

"As players, you have to have that responsibility every day and it's something my boys have to learn. Some of them they can win a big match," Mourinho told BT Sport.

"What I think they can't do is win it and win it and win it and cope with that intensity, especially that mental intensity, the focus, the concentration, the responsibility, the determination. This is something you only learn when you are at the highest level.

“I try to do it [teach and transfer it] in relation to the personality of the players. For example, what I love about this kid Marcus is he copes with the pressure. I can press him, I can be very demanding with him, he's the kind of kid that when the training session finishes it doesn't finish for him. He wants more. He lives for football.

“He was, of course, a tornado, when he arrived last season without pressure. No responsibility. And this season when the pressure was on him, when he was not scoring goals for one, two, three, four months, he coped with that pressure. This is the kind of character I like. I like to squeeze the player and the player to cope with it and react to it.

"For me what's more difficult [as a manager] is the fragile mentality.

“I think it's probably my weakness as a manager, that it's difficult for me to understand people with a different mentality to what I have.

"It's difficult to understand so it takes me time to understand and sometimes I'm not able to feel attracted again [to the player].

“Sometimes I ask my assistants to help me on that because maybe they have a different profile to me. Because for me I want to be in love with the player with this character, with this personality and that kid Marcus is the best example of it, especially in this club."