Rome:Serena Williams was upset by Patty Schnyder 6-3, 2-6, 7-6 (5) in the Italian Open quarterfinals.
"I'm going to obviously want to work harder and just do some things differently," Williams said. "Where I am today, in Paris I'll probably be even better."
In the semifinals, Schnyder will face third-seeded Jelena Jankovic, who routed Elena Dementieva 6-2, 6-1.
Second-seeded Svetlana Kuznetsova beat sixth-seeded Dinara Safina 6-1, 6-3 in an all-Russian match, and will next play ninth-seeded Daniela Hantuchova, who took took two and a half hours to defeat unseeded Anabel Medina Garrigues 7-6 (8), 7-5.
Williams third loss
Williams lost for only the third time this season. She began the year by winning the Australian Open for her first Grand Slam title in two years.
"I just didn't make the shots I was supposed to make," Williams said. "I probably made 50 unforced errors, which is pretty good to get to 7-6 in the third."
Williams captured her first two matches in Rome in straight sets and won only three fewer points than Schnyder.
"It was a nice (few) rounds. It's good to be here on the red clay and get some good matches and a lot of long points under your belt," Williams said.
Last month, Williams retired from a match in Charleston, South Carolina, with a groin muscle problem and pulled out of the Fed Cup with inflammation in her right knee. She missed the last two French Opens with knee and ankle injuries.
"Actually, not winning today is going to work well for me," she said. "I'm going to get even more fit."
Williams does not plan to play again before Roland Garros, which begins in nine days.
"I think the best thing for me now is practice," she said. "I feel like I'll really enjoy myself there."
The 14th-seeded Schnyder, who was runner-up here two years ago, also beat Williams in their only previous match on clay. Williams won the other six meetings.
"I have more time to think and I think it's her weakest surface," Schnyder said. "I'm extremely happy that I could do it again this year, because she's the champion to beat this year."
Eighth-seeded Williams struggled in the first set, missing backhands and committing double faults. Schnyder, a Swiss left-hander with a crafty all-court game, simply kept the ball in play until the American missed.
"I don't have the big muscles, the height, and so I need to get something special to my game and that's what I work on," Schnyder said. "I can play all the spins _ the slice and kick and the fast serve."
Schnyder took a 2-0 lead in the second set before Williams reeled off six straight games to force a third set.
Neither player dropped serve and Schnyder jumped to 5-2 in the tiebreaker. Williams crawled back to 5-5, but then netted a forehand and Schnyder hit an approach winner on her first match point.
Schnyder reached the German Open quarterfinals last week, and will be playing in her first semifinal of the year.
"This win is definitely a breakthrough for me," she said.