The Red Devils signed the England international in a £80m deal from Leicester City last week after months of speculation linking the English defender with a move to Old Trafford.
Manchester United made Maguire the most expensive defender in the world after his transfer fee surpassed the £75m that Liverpool FC spent on Virgil van Dijk in 2018.
Maguire has never played in the Champions League or the Europa League despite being the mostly costly centre-half in world football.
The 26-year-old will be tasked with improving a Manchester United defence that conceded more goals than Manchester City and Liverpool FC combined last term.
Former Liverpool FC captain Redknapp believes Maguire can trigger a change at Manchester United.
“It seems like there is something fundamentally wrong with that dressing room,” Redknapp told Sky Sports. “There are too many players who don’t feel that passion to play for Manchester United.
“By signing someone like Maguire – a warrior, someone who wants to win and knows the game, is technically sound and a good defender – you can start to change that whole process that has been going on over the past two years.
“Make no mistake about it, £80m is an awful lot of money for a defender – it’s astronomical. It’s too much money, but United have got a really good defender that will hopefully change the dynamic.”
Manchester United finished in sixth place in the Premier League table last season to miss out on a spot in the Champions League.
The Red Devils signed Maguire, Crystal Palace defender Aaron Wan-Bissaka and Swansea City midfielder Daniel James in the summer transfer window.
Manchester United haven’t won the Premier League title since 2013 or the Champions League since 2008.
The 20-time English champions will be hoping to end a two-season trophy drought under Ole Gunnar Solskjaer this term.
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