The aura of invincibility that has surrounded Serena Williams for the past year is starting to break down.
With little more than a week before Williams defends her title in the French Open, the top-ranked American lost Saturday for the second time in two tournaments.
The 1-6, 7-5, 6-3 defeat to Amelie Mauresmo in the semifinals of the Italian Open was highlighted by Williams' failure to serve out the match while leading 5-4 in the second set.
Such glaring missed opportunities were a rarity for Williams when she claimed her so-called "Serena Slam" by winning four consecutive majors starting at Roland Garros last year and concluding at the Australian Open in January.
Saturday's loss was only William's second this year, but both have come recently and both have come on clay, the same surface used in Paris.
Williams, who was also the defending champion in Rome, missed a tricky backhand volley while up 5-4 in the second set that gave Mauresmo a break to get back on serve. Mauresmo promptly won three straight games and stretched the match into a third set.
After trading breaks early in the final set, Mauresmo broke again to go ahead 5-3 when Williams' shot was called long on an overrule by the chair umpire.
Helped by four errors from Williams, Mauresmo then served out the match.
"Everything went wrong for me," Williams said. "I was making too many errors and struggling with my serve. I guess that sums it up. You can't win a match with a second serve.
"There was nothing in particular she did. When I lose a match it's usually because of how I played. In the end it's better to lose in Rome than in Paris."
Williams had cruised through the first set in just 21 minutes as Mauresmo -- the No. 4 seed from France -- won just four points in the first five games.
Mauresmo is attempting to win her second title of the year after defeating Williams' sister Venus in the Warsaw final two weeks ago. She beat Jennifer Capriati in the quarterfinals on Friday.
In the final of this US$1.3 million event, Mauresmo will meet second-seeded Clijsters, who did not have much trouble in defeating the 13th-seeded Sugiyama.
Perhaps slightly unnerved by waiting longer than expected for the Williams-Mauresmo match to end, Clijsters lost her serve in the opening game.
After a quick recovery, however, Clijsters was the same dominating player she has been in each of her matches here thus far. She improved to 4-2 in head-to-head matchups against Sugiyama, who is Clijsters' doubles partner.
The Foro Italico crowd did their best to encourage Sugiyama, who was the first Japanese semifinalist in the tournament's history. One fan held aloft a sign written in Japanese that read: "Let's Go Ai."
Kim Clijsters, defeated Ai Sugiyama 6-3, 6-2 in Saturday's other semifinal. In Sunday's final, Clijsters will be aiming for her third title of the year. Clijsters and Mauresmo have split their previous meetings with two wins each.
In the doubles final, 46-year-old Martina Navratilova and 17-year-old Svetlana Kuznetsova will meet Jelena Dokic and Nadia Petrova.
Agustin Calleri and Guillermo Coria will meet in the final of the Hamburg Masters.
On a historic tennis day for Argentina, Calleri beat David Nalbandian 6-4, 6-1 on Saturday and the 12th-seeded Coria overcame Gaston Gaudio 6-3, 6-7 (3), 6-0.
Never before had four players from Argentina reached the semifinals at one ATP tournament. It was also the first time four countrymen contested the semifinals of a Masters Series, the nine tournaments that rank just below the Grand Slams.