The Chirp

Serena Williams Upset at U.S. Open

Serena Williams headed into her U.S. Open semifinal against Roberta Vinci two wins away from completing a calendar-year Grand Slam.

There will be no Grand Slam. Vinci defeated Williams, 2-6, 6-4, 6-4, stunning the tournament’s No. 1 seed to reach her first Grand Slam final. As the upset unfolded, athletes from across the sports world took to Twitter to react: