Martial suffered a nasty clash of heads with Daryl Janmaat in the 26 minute, but managed to carry on until a brutish challenge from Miquel Britos on 34 minutes – a clear foul missed by referee Michael Oliver, leading to Watford’s opening goal – forced the youngster off for good.
Speaking after the game, Mourinho was unable to shed light on the severity of Martial’s injury.
“I had to be on the game at that time and not worrying with Anthony,” Mourinho said.
“I have not had time to see about the situation. It wasn’t an action to go to hospital. It was an action for a free-kick against Watford and obviously not a goal.”
“I don’t know, I promise I don’t know. You are asking about things I cannot tell you.
“I didn’t know why he came off, whether he was injured in his knee, his ankle or his head. I don’t know. I just know, in that moment, he is not in a condition to carry on. I don’t know why. I just know I had to change. I don’t know yet what happened.”
The decision to keep Martial on the pitch following such a grim head collision was foolish, and ended up costing Manchester United dearly.
It was evident that the Frenchman, whilst willing to carry on, was still partially disorientated after an extensive withdrawal from proceedings to clear the cobwebs. The truth is, however, that the effects of head trauma never immediately subside, and many – all with far superior medical knowledge than myself – have pleaded for head collisions to be treated with even greater care.
What happened with Martial is a case in point: clearly struggling, the Frenchman was unfairly clattered, doing himself – and the United side – more damage as a result.