That isn't the point though. It's the fact that whenever he performs well, Mourinho drops him for the subsequent game. Against Middlesbrough, he was excellent but was then dropped for the game against West Ham. Excellent against Reading; dropped against Hull. Contrary to what some would have you believe, he wasn't poor against Liverpool. Their RB struggled against him, and Liverpool adapted and swarmed Martial with at least three players. The problem wasn't Martial in that game. A couple of days ago, he assisted two goals and put in a good performance (not as good as the aforementioned games), yet he's still benched for a player who clearly isn't a wide forward (might perform better on the right though). Mourinho has no problem playing Rashford in consecutive games, despite his poor form. That's odd.
Just like Mourinho's insistence on playing Fellaini at the start of the season ahead of Carrick, this is another episode of him wanting to prove a point. Which is stupid because we're bleeding because of it, yet it seems that he'd rather cost us points than do the right thing. Nothing new of course - he's always been like that.