If she thought the ref made a bad call, the proper way to deal with it is challenge her call with the judges, not threaten to shove a f-ing ball down her throat.
There's simply no excuse for that kind of behavior AT ALL, no matter if the ref made a bad call or not. This wouldn't have happened had Serena had some proper upbringing and manners.
I don't feel one bit of sorry for either of the "twins"...they've shoved their finger at the American public for so long, its coming back to bite them in their very big behinds.....