Sources close to the Everton striker had maintained all along that he had wanted to return to Chelsea, the club he left in 2014.
But his agent, Mino Raiola, is close to United and Lukaku was recently on holiday in Los Angeles with Red Devils midfielder Paul Pogba.
The striker is understood to have extended his stay in LA where he will undergo a medical ahead of his move to Old Trafford.
United’s offer of £250,000 a week is believed to have clinched the deal – even though Chelsea could have easily matched that offer and indeed were reported at one stage to have agreed terms with the 24-year-old.
Even though Chelsea have yet to officially rule themselves out of the chase, Jose Mourinho’s £75m swoop for a striker his former club appeared certain they would get this summer, will infuriate manager Antonio Conte.
He had made Lukaku his No1 striker target for the summer and the club may now have to turn to Real Madrid’s Alvaro Morata, Torino’s Andrea Belotti – or even Arsenal forward Alexis Sanchez.
Chelsea’s situation is complicated by their inability yet to sell Diego Costa, the Spain striker who Conte told by text last month that he was not required for next season.
Costa, who has said goodbye to several Chelsea players already, has made it clear that he only wants to return to Atletico Madrid. The Spanish club are believed to be set to make a bid this coming week – but they cannot actually sign players until January.
Conte, who sources in Belgium claim had been in personal contact with Lukaku in the past few weeks, had wanted the deal tied up by the time his players return for training on Monday.
Chelsea believe deals for Monaco midfielder Tiemoue Bakayoko and Roma defender Antonio Rudiger are close to being completed but the loss of their main striking target would be a blow.
