The Red Devils are yet to sign any players during the January transfer window but have been linked with a host of stars during the course of the month.
Benfica attacking midfielder Sanches has emerged as one of the names to be relentlessly linked with a big-money move to Old Trafford in recent days.
Now, Portuguese newspaper O Jogo is reporting that United have tabled a bid of around £31m to sign the 18-year-old before the deadline and are in advanced talks to bring the player to Old Trafford.
It is understood that Sanches has a release clause of around £60m in his current contract with the Portuguese side but the Red Devils are negotiating hard on the price-tag.
United booked their place in the fifth round of the FA Cup on Friday night with a 3-1 victory over Derby County.
The Red Devils host Stoke at Old Trafford in the Premier League on Tuesday.
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