Manchester United are confident of wrapping up a stunning £75 million deal for Everton striker Romelu Lukaku before the club leave for their US tour on Sunday, despite Chelsea refusing to throw in the towel.

Chelsea believed they were favourites to sign Lukaku but have been left blindsided by United’s dramatic hijacking as Jose Mourinho prepares to be reunited with a player whom he allowed to leave Stamford Bridge three years ago.

United have been happy for talk of Lukaku going to Chelsea to gather pace in recent weeks while they worked quietly behind the scenes to secure Mourinho’s first-choice target to replace Zlatan Ibrahimovic.

Chelsea, though, are exploring whether there is any scope to launch an 11th-hour bid for Lukaku after being convinced the 24-year-old wanted to move to West London and with United still to formally complete a deal.

But having agreed a £75m fee with Everton, United are optimistic that Lukaku will be their player by the time the squad fly to Los Angeles on Sunday for the start of their two-and-a-half-week pre-season tour of America.