Questions about example sentences with, and the definition and usage of "Nadal"

A: Break someone's service is a phrase used when you win a game in a tennis match against the opponent's service.

A: Are you still working hard?
Are you working hard still?

A: "Play with" can have various meanings - a child can "play with" a toy, you can play a casual game of tennis with a friend, you can play with your food by just moving it around your plate and not eating it.
If Nadal was playing doubles on the same side as Djokovic, you could say he was playing with him.