text: Serena Reaches Fourth Round of U.S. Open (AP) AP - Hardly at her best, barely beating one of the tour's pesky teens, Serena Williams suddenly found herself face-down at the U.S. Open. Running for a ball she couldn't reach, the six-time Grand Slam champion slipped and planted both palms on court to brace herself. Williams shook the sting out of her hands, beckoned a ball boy to retrieve her fallen racket, then took her sweet time before facing break point. Recomposed, Williams smacked a service winner at 111 mph, an ace just as fast, and forced an error. Just like that, she held serve en route to beating 30th-seeded Tatiana Golovin 7-5, 6-4 Friday night to reach the Open's fourth round.