The Red Devils have all but conceded this season’s Premier League crown after Manchester City pulled 15 points clear of the bitter local rivals after this week’s fixtures.
Manchester United moved quickly to snap up Sanchez from Arsenal last month and agreed to let Henrikh Mkhitaryan head to The Emirates as part of the same deal.
Sanchez endured a Premier League debut for Manchester United to forget on Wednesday night when they were comprehensively beaten by Tottenham at Wembley.
However, former Spurs manager Redknapp is still backing the Chile international to make a huge difference at Old Trafford in the coming seasons.
Speaking to BT Sport on Wednesday night, Redknapp said: “Sanchez will take them to another level for sure.
“I think he’s the missing part of that big jigsaw in a team that’s probably going to go on and win a title again under Jose Mourinho.”
Sanchez will be hoping to help Manchester United return to winning ways in the Premier League on Saturday afternoon when they take on Huddersfield Town in front of their home fans at Old Trafford.
The Red Devils finished in sixth place in the Premier League last season, Mourinho’s first campaign in charge, and they have not won the title since Sir Alex Ferguson’s final campaign in charge back in 2013.
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