The 26-year-old Argentina international is expected to fly into Manchester on Monday to hold talks with United next week with the hope of being ready to face Burnley at Turf moor next Saturday.

When the transfer is finalised, the fee will be a record in Britain, eclipsing the £50m Chelsea paid for Fernando Torres three years ago.

According to Sky Sports’ Spanish football expert Guillem Balague, United initially offered €60m and Madrid wanted €90m, with the two clubs eventually agreeing on €80m (£63.9m).

Manchester United have declined to comment on whether a fee has been agreed.

After watching United stumble to a 1-1 draw at Sunderland on Sunday afternoon, Gary Neville told Sky Sports: “It’s good business. United have lost their negotiation strength but they just need to get the right players. This one is.

"He'll get pace into the game and get from box to box. He’s the right signing. You could argue they need other players in other areas but they definitely need a wide player.”

United manager Louis van Gaal refused to confirm or deny a deal had been agreed for the Argentine in his post-match interview with Sky Sports.

“The club has to announce it,” he said. “When we are thinking it is the right time for a transfer, then we come to you and say ‘OK, we have that player or the other player’. But at this time we cannot say anything.”