Zurich:Amelie Mauresmo was upset by Alona Bondarenko 2-6, 6-4, 6-1 on Wednesday in the second round of the Zurich Open.
Mauresmo dominated early, taking a 3-1 lead in the first set, but last year's Australian Open and Wimbledon champion fell apart after being broken at 4-4 in the second.
The former top-ranked Frenchwoman, who has struggled since an appendectomy in March, was broken twice in the third set.
"This was my best tennis in a long time," Mauresmo said. "But physically I'm not at my top and it's a question of confidence, too.
"I have to gain confidence by winning matches like this one but it didn't happen. And physically I'm just not at the level I've been the last several years."
Bondarenko, who has won only one WTA Tour title, said she was nervous in the first set.
"But I concentrated on my game instead of the fact I was playing Amelie Mauresmo," the Ukrainian said.
Mauresmo is now looking forward to some rest.
"It's been a tough season for me," Mauresmo said. "Now it's behind me. I'll take a little break before getting back to work because that's what I need."
The 18-year-old Czech Nicole Vaidisova defeated third-seeded Jelena Jankovic of Serbia 6-4, 6-4.
Having played 93 matches this season, Jankovic has recently complained of fatigue. Last week, she retired with heat exhaustion from the first round of the Bangkok Open.
"I'm just tired. I need some rest," Jankovic said.
Wimbledon finalist Marion Bartoli also advanced to the quarterfinals, beating Michaella Krajicek of the Netherlands 6-4, 6-1, and Tatiana Golovin of France upset fifth-seeded Ana Ivanovic of Serbia 6-3, 6-1. Francesca Schiavone won her first round match after Elena Dementieva retired with left thigh injury while trailing 4-6, 6-1, 4-2.
It marked only the second time in eight matches that Golovin defeated Ivanovic.