A year ago, U.S. Open fans fell for Novak Djokovic. They loved his stylish play and, more so, his wit and his shtick. They cheered raucously when Djokovic stuck around after winning his quarterfinal and, prompted by a TV interviewer, did spot-on impersonations of Maria Sharapova (pretending to tuck his hair behind his ears, exactly how the Russian does) and Rafael Nadal (even yanking at the back of... More...