TOKYO (AFP) - Unseeded Estonian Kaia Kanepi toppled world number one Caroline Wozniacki in the Pan Pacific Open tennis tournament on Wednesday, dashing the Danes hopes of defending her title in Tokyo. The 21-year-old Wozniacki, playing her first tournament since her semi-final exit at the US Open two weeks ago, bowed to the 43rd-ranked Estonian 7-5, 1-6, 6-4 in the third round. I felt I played some good tennis in the second set, and a half in the third. I had 3-0 (in the final set), and my serve ... I just couldnt get any first serves in. I think I should have won that match, said Wozniacki. Kaia played a good match today, played aggressively and she won the match. Shes been top 20 before and she had some problems with injury. Thats why her ranking dropped a little bit. Ill try to do better next time. Kanepi stormed back from 0-3 down and then 2-4 down in the final set before taking the following four games in a row. Although she needed three match points, she punished Wozniackis short ball on the third match point with a clean forehand winner to finish off the two-hour-23-minute battle. It feels great, said Kanepi. Of course, Im very happy, not because I beat her, but also because I played well and I hung in there. I went there to play my game, not take too many risks, just to play long points, and stay aggressive. I think the game from the baseline, I was staying aggressive. My serve sometimes didnt work well, but overall everything is fine, she added. It was Kanepis first win over Wozniacki in three meetings. Meanwhile, crowd-favourite Maria Sharapova needed just over two hours to defeat Germanys Julia Goerges 7-6 (7/4), 7-6 (7/4) and set up a revenge match against Wimbledon champ Petra Kvitova. The 21-year-old Czech, who defeated Sharapova in the final to claim her first Grand Slam title at Wimbledon in July, outclassed American Vania King 6-1, 7-6 (7/4) to reach the quarter-finals. I have a tough loss against her (Kvitova) at Wimbledon, Sharapova said of her two-set defeat to the Czech. I hope I can learn from the match and raise my level. No matter how good she plays. Im looking forward to it, she said. Her compatriot Maria Kirilenko, who eliminated US Open champion Samantha Stosur of Australia in the second round, kept her momentum by beating former world number one Ana Ivanovic of Serbia 6-3, 6-1. Fourth seed Vera Zvonareva of Russia whipped Iveta Benesova of the Czech Republic 6-1, 6-2, while seventh seed Marion Bartoli of France breezed past Chinas Peng Shuai 6-2, 6-1.