(CNN) -- Former Wimbledon champion Petra Kvitova became the first big name seed to exit the star-studded WTA tournament in Tokyo as she fell victim Tuesday to unheralded Croatian Petra Martic.
Fourth seed Kvitova was well below her best in the second round match at the Pan Pacific Open and three double faults in her opening game to lose serve left the Czech on the back foot.
Martic, who has been sidelined by injury, took full advantage to take the first set and after claiming the first game of the second to love, was always in command.
A 6-4 6-4 win was the biggest of her fledgling career and followed a remarkable first round victory over Andrea Petkovic of Germany, where she trailed 6-0 1-0 before recovering to win in three sets.
Kvitova, who will now head early to Beijing for her next tournament, admitted she had been outplayed.
"She has a big serve and it is tough to push her. She kept me on the defensive and running a lot, and that's not my game," she told the official WTA Tour website.
"She played so well today, very aggressive," Kvitova, 22, added.
World No.2 Maria Sharapova also faced an early exit when she trailed British qualifier Heather Watson by a set, but she hit back in typical style to grind out a 6-7 6-3 6-4 win in over three hours. .
"I was not consistent enough. I had opportunities to win the first set and I didn't," said Sharapova.
But former World No.1 Caroline Wozniacki continued her more impressive recent form with a 7-6 6-1 dismissal of Slovakia's Daniela Hantuchova.
Dane Wozniacki took her first WTA Tour title in more than a year in Seoul last week as she bids to re-enter the top 10 after a recent slump.
Current No.1 Victoria Azarenka of Belarus also looked in fine fettle after her U.S. Open heroics where she lost a superb final to Serena Williams.
She beat Tamira Paszek of Austria 6-1 6-1, while defending champion Agnieszka Radwanska of Poland saw off Jelena Jankovic of Serbia 6-2 7-5.
Last year's French Open champion Li Na of China and ninth seed Marion Bartoli of France also progressed.