Real Madrid and Barcelona were seemingly at the front of the queue to sign Willian, but the 29-year-old's latest comments will only intensify rumours that a move to United is a strong possibility, with the player admitting that he is regularly in contact with Mourinho.
Jose Mourinho is desperate to sign a centre-back before the summer transfer window closes and German World Cup victor Boateng, 29, has emerged as a serious target for the Red Devils.
There has even been speculation of a swap deal involving wantaway United forward Anthony Martial and Boateng ahead of the 2018/19 campaign.
German media outlet Kicker, as quoted by Metro, is reporting that Manchester United are facing competition from League Cup runners up Arsenal and Ligue 1 champions Paris Saint-Germain. To me, he's one of the best central defenders in the world'.
Former Manchester United and Chelsea CEO Peter Kenyon has urged Jose Mourinho and Ed Woodward to learn to work together better in order to bring the glory days back to Old Trafford.
"It will get worked out and I would hope Jose is part of that working it out because he is incredibly skilled and he's demonstrated he can do things".
'We'd all be sad, ' the Austrian said.
It doesn't seem like the most outrageous of claims to suggest that managers should be able to coach the best out of their players, which begs the question, why shouldn't every manager feel the same? Or they are investing massively like Liverpool, who are buying everything and everybody.
Fred, Diogo Dalot, and Lee Grant have been the only three arrivals at Old Trafford so far and Mourinho has warned the club that it could be a hard season for Manchester United this season.