I hate to say it. Rashford isn't much of a threat on his own. Given space, maybe. But for the most part, he is too passive when he doesn't have direct interaction with the ball and too undecisive when given the chance to take action. I feel the same way about Martial, even though he is better in possession. It's one of the reason's Greenwood will be much better than those two. When Greenwood has the ball in and around the box, he's usually crafting a quick decision, and even if the decision doesn't go as planned, he won't delay it the next time. He plans his moves ahead of time.
The reason I am saying this is because I felt our defence were very good in handling Chelsea's attack, but I don't think chelsea's defence had to worry nearly as much as ours did when being directly attacked. When Werner, Havertz or Pulisic were given a good pass from their midfield and they had the advantage in space, they were very aggressive and almost created something out of it. However, when we gave James and Rashford ( Martial and Rashford on tuesday) the same opportunties as those players ( Mbappe, Neymar, Werner, Havertz, Pulisic), our players folded, rather than the defence stopping them.