Canadian qualifier Aleksandra Wozniak beat Australian lucky loser Samantha Stosur 6-2 5-7 6-4 in the quarter-finals of the Bank of the West Classic today.
Stosur made the main draw despite losing in qualifying to Wozniak because Lindsay Davenport withdrew with a right knee injury.
Serena Williams will take on Wozniak in the semi-finals.
Williams spent more time waiting for her quarter-final match to start than she did on the court against Patty Schnyder.
Neither activity proved to be too stressful for the top seed.
Williams advanced to the semi-finals with little trouble on Friday, beating the fifth-seeded Schnyder 6-3 6-1 in 54 minutes.
The match began more than an hour later than scheduled because Ai Sugiyama of Japan needed 2 hours, 44 minutes to win her quarter-final over Dominika Cibulkova of Slovakia 6-7 (4-6) 7-6 (7-5) 5-3. Cibulkova retired because of cramping in her left leg with Sugiyama serving at 40-0 for the match.
But that extra delay proved to be no trouble for Williams.
"No one can kill time the way I can," she said.
"I'm a professional time killer. I can sit for three hours and I couldn't tell you what I did. If it was an Olympic sport I'd be a 20-time gold medal winner."
Schnyder had won three of the last five meetings against Williams, including a match in Zurich last year when Williams retired after losing the first nine games. But Schnyder was unable to find her groove against Williams this time and went down meekly.
Williams opened the match with three straight forehand winners, and the result was never really in doubt despite Williams hitting four double faults in her first two service games and five overall.
"I don't think I served well," she said.
"I don't hit double faults as a rule. It was kind of weird for me to make all those double faults. It was kind of frustrating."
Williams rolled off the final six games to advance to the semifinals in her debut at this tournament. Williams decided to come to Stanford because of the low stress level of this tournament.
After losing the first set of her opening match to Portuguese qualifier Michelle Larcher de Brito, Williams has had little stress.
"To be honest, it's an easy draw. It's four matches if you get a bye," she said.
"It's tough to come across a draw like that. Plus I've been here before and I thought the facility was no nice, just so relaxing. It just feels like it's such a relaxing tournament."
There was much more drama in the first quarter-final when Sugiyama overcame three match points in the second set before advancing to play the winner of the match between defending champion Anna Chakvetadze, the second seed, and sixth-seeded Marion Bartoli in the semifinals.
Cibulkova won the first set in a tiebreaker 7-4 and led 5-2 in the second before faltering. Sugiyama held serve and then broke Cibulkova to get back on serve.
Sugiyama then fell behind 0-40 on her own serve in the 10th game before rallying to win five straight points to even the set. She went on to force a tiebreaker and won 7-5 to force the third set.
"I still can't believe I came back from that position," Sugiyama said.
The final game got interrupted by an injury timeout and then another delay when audio from a nearby fashion show was accidentally piped into the stadium, forcing the players to wait out the distraction.
