Serena strolls into Stanford semis

Sugiyama battled back from the brink of defeat, saving three match points in the second set, and was leading 6-7 (4/7), 7-6 (7/5), 5-3, when the match was halted.

"I wasn't really feeling heavy and was moving quite well from the beginning of the match," Sugiyama said. "Even at the end, I felt pretty fresh and kept eating my energy bar throughout the match."

Sugiyama will face sixth-seeded Marion Bartoli of France, who upset second seed and defending champion Anna Chakvetadze of Russia 6-3, 6-4.

Chakvetadze, 21, had hoped a move to the US hardcourts would help turn around a so-far disappointing season.

Last year she won this tier 2 event, as well as in Cincinnati, and reached the semi-finals at San Diego and the US Open.

Ranked eighth in the world, she has won one title this season, but reached te semi-finals just once in 10 events since. On Friday, she was undone by 38 unforced errors.

Bartoli, too, arrived in the States for the build up to the US Open seeking consistency.

The 2007 Wimbledon finalist and world No. 15 has yet to appear in a final this year.