Is this the changing of the guard in tennis? Sloane Stephens, 19, won an upset victory against Serena Williams in the quarterfinals at the Australian open on Wednesday. Williams won the first set 6–3, but Stephens came back to dominate the second set 7–5 before capping off the match with a 6–4 victory. Williams said she suffered a back injury at a point close to the net, but the match overall proved frustrating—causing her to take out her anger on her racket, which she broke when she slammed it down during the second set. On Tuesday, Williams and sister Venus lost in the doubles quarterfinals.