This performance made me want to go with the cliche that he's not brave enough at times. Seems like to choose not to take responsibility when the opponent turn on heat (this game = harassing).
We definitely still needs that young Rooney, Ronaldo, in form Nani & Valencia the winger... who force thing when it gets tough. Trying to go around through the pocket of space doesn't always work.
Edit: just to clarify before someone turned this into another Martial debate, IMO Martial doesn't demand the ball/ get involved enough at times. He's good and positive with the ball, but off the ball, there is much to be desired from him. His involvement to me is like a central forward, but then his role is wide forward/ winger. IMO, the above players really get involved a lot and try to influence the flow of the game for good or for bad. Someone like Rashford & Lingard definitely looks to get involved more than Martial, but they have their own flaw as they're not wiz dribblers like Martial, which is natural ability that can't be learned. If only Martial's willing to learn (what is coachable like LVG put it) and improve, then we're good