Erik ten Hag wants Maguire to replicate England form at United
Maguire lost his first-team spot for United in August but then started every game for England in Qatar, where they were knocked out in the quarter-finals by France.
"It's clear he is good enough to play at the highest level," Ten Hag said at United's training camp in Spain.
"He had a period in Manchester where he performed badly and then, of course, there are difficulties. For England, he has good games almost all the time.
"We want him to bring that back to Manchester with him so he can bring it on the pitch for United.
"I think he had a really good World Cup. He was really consistent. When he is playing with his confidence like now, he is a massively important player for us and that is what everyone expects."
United return to action on December 21st with a home League Cup tie against Burnley before hosting Nottingham Forest in the league on December 27th.