Mainoo is slightly behind some of his team-mates in pre-season preparation after being involved with England at the 2026 FIFA World Cup. However, Carrick has been impressed by the midfielder's attitude since his return to United.

The 21-year-old did not feature for England during the tournament, but Carrick believes the experience will ultimately benefit him.

"I've only seen positives since he came back," Carrick said. "Since he returned, you could see that he was delighted to be here. He had a break and it was important that he went away and switched off."

Carrick particularly admires Mainoo's determination to deal with difficult moments.

"Kobbie is strong. He's had some huge highs and some challenging times already in his career, and he's only 21, which is incredible," the United boss said.

"But he's got that stubbornness about him that I love in a footballer, where he deals with things so well.

"He's been great in training, he's ready for a big season and that experience with England will help him."

Mainoo's disappointment at the FIFA World Cup was understandable, according to Carrick, but the midfielder has already moved forward.

"It's frustrating because he wanted to go and play and do more obviously but, sometimes, you've got to learn from other things," he said.

"We're there to support him and I've certainly tried to be there for him during the summer. But he's in a really good place, and I'm looking forward to seeing him play this season."

Carrick also has decisions to make in midfield for Saturday's Premier League opener against Hull City, with Bruno Fernandes expected to operate in an advanced role.

New arrivals Youri Tielemans and Andrey Santos have also impressed during their early time at the club.

Carrick said Tielemans has adapted well despite joining the squad late.

"Youri has done what we all expected," he said. "He's ready to go, and although he did come back late so he's not had the full pre-season with us, we've been settling him in and getting him up to speed."

Santos has caught the eye with his ability to move the ball forward while also contributing defensively.

"Andrey takes the ball so well, passes the ball forward a lot, understands the positioning of his team-mates and sacrifices himself to make the team better, which is always important," Carrick said.

"He's very good defensively. He can read the game in an intelligent way and he's a fantastic character."

Hull City stun Man Utd on Premier League return