Samantha Stosur earned the biggest victory of her career as she downed Serena Williams 6-2, 3-6, 6-2 at the Bank of the West Tournament. Serena had admitted yesterday that she was having trouble with her serve, and as if to confirm her problem she served a double fault on match point.
Stosur saved nine of 10 break points on Friday and played a steady game against the top-seeded Williams, who had a nine-match winning streak snapped.
Stosur is seeking her first WTA Tour title.
Third-seeded Elena Dementieva of Russia also advanced to the semifinals, beating Daniela Hantuchova of Slovakia 6-2, 6-4.
Dementieva will play the winner of the match between Maria Sharapova and Venus Williams.
Stosur will meet the winner of the Jankovic/Bartoli match in the semi final.