TORONTO (Reuters) - World number one Caroline Wozniacki headlined the parade of seeded players to fall at the Toronto Cup with a shock loss Wednesday while Maria Sharapova and Serena Williams moved into the last 16.
Defending champ Wozniacki rarely looked comfortable on court and did not live up to her top seeding with seven double faults and a slew of errors during a 6-4 7-5 loss to Italy's Roberta Vinci in windy conditions that played havoc with her game.
A day after second seed Kim Clijsters dealt the tournament a blow by retiring from her opening match with a partial tear of a stomach muscle, it was Wozniacki's turn for a premature exit.
"I didn't get a chance to really get any rhythm, it was difficult first with the wind but also the way that she was playing," Wozniacki, who became the seventh seeded player to exit the tournament in Toronto this week, told reporters.
"Right now it's pretty disappointing and you just try to get over this match and just try to analyze what happened and take the positives and negatives and try to improve."
After dropping the first set, Wozniacki raced into a 5-1 lead and seemed poised to force a third set but was unable to close it out as she served into the wind, which on several occasions interrupted her service tosses.
"I came against the wind for the next two games and it was pretty difficult on the other side and she served well and that pretty much just summed everything up," said Wozniacki.
"On one side the wind was blowing in the back and you had to watch out you didn't play it long, and on the other side you really had to hit through the ball to make it even go."
Wozniacki headed a solid Toronto field that boasted the top 20 women players in the world, but Williams, unseeded after an 11-month layoff that ended in June, has grabbed the spotlight.
After barely breaking sweat in a 46-minute opening match against Alona Bondarenko, Williams was forced to work a little harder to get by Germany's Julia Goerges 6-1 7-6.
The 13-times grand slam winner said she had been calmer on court since her return and was enjoying the lack of pressure as an unseeded player and did not have "anything to lose at all."
"It puts me in a wonderful position and such an easy position to be in," said Williams, who won the Stanford Classic in her third tournament back.
Sharapova, who had a first-round bye, jumped out to a fast start but needed to dig deep for a 6-1 7-5 win over Bojana Jovanovski after the Serbian qualifier gained a 4-2 lead in the second.
Swirling winds made for some challenging play and Sharapova needed to make adjustments in the match to hold off a spirited challenge from Jovanovski.
"The conditions were tough for everyone today and it's not always the best tennis when you are facing those conditions, but it goes both ways," Sharapova told reporters.
"Not just for yourself but also for the opponent so it's just a matter of who handles it better and who adjusts and makes adjustments at the right time."
Third seed Vera Zvonareva of Russia dumped compatriot Nadia Petrova 7-5 6-4, earning herself a matchup against Agnieska Radwanska in the last 16.
Editing by Peter Rutherford