Jose Mourinho in the dark over Ander Herrera's injury in Manchester United's win over Real Madrid

One downside of the win in Santa Clara was the injury to midfielder Herrera who was forced off just minutes into the second half

Jose Mourinho watched on as Manchester United beat Real Madrid (Manchester United)

Jose Mourinho says he remains in the dark over the injury that forced Ander Herrera during Manchester United's pre-season win over Real Madrid.

Jesse Lingard and Casemiro swapped goals in regulation time in Santa Clara before David De Gea saved two spot kicks in the penalty shootout in a 2-1 victory.

One downside of the win was the injury to midfielder Herrera who was forced off just minutes into the second half.

"It is at least very painful because for Ander to come out it has to be very painful," Mourinho said. "I want to wait and see what it is, but I also say to the players, 'No risk in friendly matches - if you feel something, if you feel that something is coming, sometimes a little muscular injury, get out'.

"The result is not important, but he was very painful, it was in front of the bench. I think it was a bad contact. Maybe ribs, I don't know. Maybe muscle, I don't know."

Anthony Martial was the standout performer for United setting up Lingard's goal with a sublime piece of skill.

Put to Mourinho that the assist underlines what a useful asset the France international can be, the United boss said: "Exactly, but obviously we want more consistency in his talent. I think today was positive for him, that's why I left him for 90 minutes on the pitch.

"He was enjoying (himself), he was trying things and it's important in these friendly matches to try things, which he did. I think was good for Anthony, for his confidence."