ROME - Serena Williams certainly didn't look ready for the French Open on Wednesday.
The six-time Grand Slam winner was upset 7-6 (2), 6-1 by Italy's Francesca Schiavone in her opening match at the Italian Open, an important tuneup for the season's first major, which starts in less than two weeks.
Williams moved poorly and was overpowered by the 26th-ranked Schiavone, who had all her shots working.
Williams called it the worst loss of her career.
"This is it for me probably for sure. It won't be happening again," she said.
In the first-set tiebreaker, a seemingly uninterested Williams didn't even run for a drop shot by Schiavone that gave her a set-point opportunity.
"I couldn't get my legs moving. It was really weird. I've never felt like this before," Williams said. "I actually had a really good warmup right before the match and I thought everything would come together, but it didn't."
The crowd supported Schiavone and rained whistles down upon Williams, who seemed lethargic throughout the second set.
The loss extended Williams' run of misfortune since winning the Australian Open in January.
Williams was forced to withdraw from the Paris Indoors in February with a stomach illness before her quarterfinal match.
In March, she retired from her semifinal with Jelena Jankovic due to a shoulder injury. Then in Miami, she lost to sister Venus for the first time in four years, snapping a six-match winning streak against her sibling.
Last month, Serena sprained her left ankle during a quarterfinal match with Silvia Farina Elia and retired after failing to convert three match points in a second-set tiebreaker.
Serena was not planning on playing another tournament before the French Open, although she said after the loss that she was going to rethink her schedule.
"I didn't expect this to happen," she said.
Serena was not the only Williams who looked distracted Wednesday.
Venus watched from the stands and appeared to be sleeping. Another member of the family's entourage in the stands played a video game.
Serena said she was fit and did not take well to one reporter's suggestion that she played as if she were on a vacation.
"I wasn't here on holiday," she said.
Schiavone improved to 8-8 this season. The Italian is still seeking her first career title since turning pro in 1998. Williams has 26 career titles.
Schiavone was forced to withdraw from her first-round match in Warsaw last month with a left thigh strain. She returned to action by beating Meghann Shaughnessy in the first round here Monday. Serena had a first-round bye.
Earlier, Amelie Mauresmo began the defense of her Italian Open title with a 6-2, 6-0 win over Australia's Samantha Stosur.
Fourth-seeded Elena Dementieva, who withdrew from last week's German Open because of a left hip injury, lost 7-5, 6-4 to Gisela Dulko of Argentina in the second round.
Dementieva, runner-up at last year's French and U.S. Opens, has never advanced past the second round in five appearances at the Italian Open.
Seventh-seeded Nadia Petrova cruised past Italian qualifier Mara Santangelo 6-3, 6-1 in her first match since losing Sunday's German Open final to Justine Henin-Hardenne.
Petrova now faces four-time Italian Open winner Conchita Martinez, who beat Israel's Anna Smashnova 3-6, 6-1, 6-1.
Also in this $1.3 million clay-court tournament, sixth-seeded Vera Zvonareva, eighth-seeded Patty Schnyder, ninth-seeded Elena Bovina and 15th-seeded Ai Sugiyama each advanced with straight-set victories; and 1997 Italian Open champion Mary Pierce eliminated Sanda Mamic of Croatia 6-4, 6-4.
Pierce, who won the French Open in 2000, next meets top-seeded Maria Sharapova, who is attempting to take over the No. 1 ranking this week.
Mauresmo, who is coming off a quarterfinal appearance at last week's German Open, said she had fully recovered from a five-week layoff with an abdominal muscle injury.
She will next face 13th-seeded Farina Elia, who rallied from a 0-3 first-set deficit to beat France's Stephanie Cohen-Aloro 6-3, 6-3.
Mauresmo beat Farina here last year over three sets in a rain-delayed quarterfinal.
"I hope the conditions are better this year. It will be a real test for me," Mauresmo said.