Serena Williams was only thinking out loud when she muttered that this Australian Open had been "the worst two weeks," but not long after a courtside microphone picked up those comments during her quarterfinal with 19-year-old American Sloane Stephens, things got a whole lot worse. Stephens outplayed Williams, whose movement and serves had been slowed by a back injury, and beat the 15-time Grand Slam champion 3-6, 7-5, 6-4.
It was Williams' first loss since Aug. 17, and her first defeat at a Grand Slam tournament since last year's French Open. Williams' downer of a Grand Slam Down Under started badly when she turned her right ankle in her opening match at Melbourne Park. "I've had a tough two weeks between the ankle ... and my back, which started hurting," Williams said. "A lot of stuff." She and sister Venus also lost in doubles. Stephens, meanwhile, advances to a semifinal tomorrow against defending champion Victoria Azarenka. (Read more Serena Williams stories.)