ok this what novak had to say about that:
Q. Maria Sharapova was in your box and also Robert De Niro. What are those two relationships with you? Somebody had to ask.
NOVAK DJOKOVIC: Yeah, I was expecting that question on the first place (laughter).
No, let's not go too much with Maria. It's just a friendship we have. It was nice from her to come and support me. As well, Robert, he was yesterday on the match, and today.
I mean, it's amazing feeling to see such a successful people, you know, in my box supporting me, playing with me I can say, living every emotional moment. It's great. It's great.
Q. What does she think of your imitation?
NOVAK DJOKOVIC: She said she's going to kill me. Of course, she accepted it on the right way. Of course, she found it funny, not offended.
pretty shocked they were frinds