I don't know wtf happened to his serve really.It was on fire the past two weeks but today it's useless to the point it's affecting his confidence it seems.He can still win this but he needs to calm down.He can only play better anyway
Because he has not faced a returner even close to Murray's level until now.
I think Murray returning during a 40-0 game is opportune for him for a variety of reasons:
1. He's is basically impenetrable right now, so he can defend and blast anytime he likes
2. It gets into Novak's head. An easy game = Murray loosens up, which makes Novak tighten up
3. Novak isn't serving nearly as well as he did during the previous rounds....and some of that is because of Murray's returning.
It's amazing how often Novak has messed up an easy game on his serve or an opening on Murray's serve. Whenever he holds, it's like from 30-30, and whenever he breaks, it's likely that Murray already had a game point