From TMZ:
Serena fired the first shot in a Rolling Stone interview recently [yes, that same interview] where she ripped on Sharapova (she didn’t mention Maria by name, but the interviewer assumed it was her) by saying, “She’s still not going to be invited to the cool parties. And, hey, if she wants to be with the guy with a black heart — go for it.”
FYI — Maria is dating one of Serena’s rumored exes.
In a pre-Wimbledon press conference today, Sharapova took out her claws and got catty … bringing up the fact that Serena is rumored to be dating her tennis coach (who is possibly still married).