Anthony Martial left Manchester United’s US tour to be at the birth of his son as the Frenchman’s relationship with Jose Mourinho reached breaking point on Wednesday night.

United were unable to confirm whether Mourinho had given Martial permission to fly to Paris from Los Angeles to be with his pregnant partner Melanie Da Cruz, but the manager was said to be fuming over the situation.

The 22-year-old winger left United’s hotel in Beverly Hills on Wednesday, telling team-mates that he has no wish to return on tour following the birth.

Anthony Martial has left Manchester United's pre-season tour of the United States early

The forward has returned home to be with girlfriend Melanie Da Cruz, who is due to give birth

Martial, who is a father from a previous relationship, is set to have his first child with Da Cruz

Martial, who also has a three-year-old daughter with his ex-girlfriend Samantha Jacquelinet, is desperate to leave Old Trafford and recently abandoned plans to move from a city centre apartment into a family home in Cheshire.

Mourinho is determined to sell Martial to fund new signings before the transfer deadline on August 9. United will demand £80million for a player who cost £36m when he arrived from Monaco in 2015.

His career at United has dipped dramatically since Mourinho succeeded Louis van Gaal two years ago, with the Portuguese coach believing Martial lacks mental strength.

Still, his sudden departure — revealed by MailOnline — is another setback to a tour that began without 12 World Cup stars and Alexis Sanchez, who missed the first week of the trip after being denied entry to the US over visa problems.

The exit comes at a bad time for the Frenchman, who is heavily linked with a summer transfer

It also emerged on Wednesday night that captain Antonio Valencia could miss the start of the season. He flew home after tearing a calf muscle in Sunday’s goalless draw with San Jose Earthquakes.

Martial played in the tour games against Club America and San Jose and was due to lead the attack against Leicester on August 10 in the absence of Romelu Lukaku and Marcus Rashford, who will not be match fit following the World Cup.

But his absence from United’s match against AC Milan in LA in the early hours of this morning, and the remaining tour games against Liverpool and Real Madrid, will put that in some doubt.

Indeed, he may have played his last game for the club if a buyer can be found in the next two weeks.

Jose Mourinho is now at breaking point with Martial and has no objection to the player leaving

Mourinho has been told he needs to sell before he can buy but the market is limited in this window.

The Old Trafford hierarchy are reluctant to trade Martial to a domestic rival such as Chelsea or Tottenham, and foreign clubs are unlikely to pay £80m.

Paris Saint-Germain, Juventus and Real Madrid have other priorities this summer, while Bayern Munich would prefer to sign him in a year’s time.

United could trigger the 12-month extension on Martial’s contract until 2020 but are aware that the player wants to quit and Mourinho wants him out.

Martial already has a young daughter, Peyton, who he posts images alongside on social media

The France forward fathered his daughter during his marriage to Samantha Jacquelinet

The Portuguese coach is keen on Inter Milan winger Ivan Perisic or his Croatia team-mate Ante Rebic as a replacement. Reports in Germany on Wednesday claimed United have made contact with Eintracht Frankfurt over Rebic.

Mourinho also wants to sign Harry Maguire from Leicester and the England centre back is convinced that he will move to Old Trafford before the window closes in two weeks.

Marcos Rojo, one of the players at risk of being sold to make way for Maguire, will not join up with the tour after sustaining an injury at the World Cup.

Nemanja Matic has also been unable to train owing to a knock picked up at the tournament in Russia and has been sent for scans as United’s trip to the US continues to be beset by problems.