During the third rounds of the 2011 U.S Open, Serena Williams did the unbelievable. Video after the jump.Known for her outrageous outfits on and off the tennis court, and of course her undeniable talent. Tennis star Serena Williams debuted a new move for spectators, when she hit a split on the tennis court. Serena also won the match that she was playing against Victoria Azarenka. Advancing to round sixteen.