Tokyo, Sep 25 (IANS/RIA Novosti): Russian World No.2 Maria Sharapova was pushed to the limit as she beat Britain's Heather Watson in a three-hour epic in the Japan Open tennis event here Tuesday.

Sharapova won the second-round tie 7-6(7), 3-6, 6-4 in a match that saw the Russian's serve broken six times out of 14 total breaks in the match.

Sharapova served erratically throughout, racking up 14 double faults, including eight in the first set alone.

Qualifier Watson continued the form she showed in beating Sabine Lisicki of Germany in the first round, but was outgunned when Sharapova recovered her form in the third set.

Earlier, World No.5 Petra Kvitova suffered a surprise second-round exit, losing to World No.73 Petra Martic in straight sets.

Kvitova went down 6-4, 6-4 to Martic in her first match of the tournament after the Czech received a first-round bye.

Martic will now play Russia's Nadia Petrova in the third round after Petrova defeated Romania's Simona Halep 7-6(4), 6-0.

Elsewhere, World No.8 Li Na battled through a tough second-round match against Russia's Anastasia Pavlyuchenkova, eventually prevailing 7-5, 4-6, 6-2, and will now play either Caroline Wozniacki or Daniela Hantuchova.

World No.10 Marion Bartoli moved into the third round with a win over Germany's Julia Goerges, triumphing 6-2, 7-5, and will now face Sara Errani.

French Open finalist Errani secured her passage to the third round with a 6-3, 7-6(1) win over Johanna Larsson of Sweden.

World No.15 Kaia Kanepi was knocked out 5-7, 6-2, 6-3 by unseeded American Jamie Hampton, just two days after the Estonian had played in the final of the Korea Open, losing to Wozniacki in Seoul.

Hampton's next opponent will be either World No.3 Agnieszka Radwanska or former U.S. Open champion Jelena Jankovic, who play later Tuesday.

Radwanska's younger sister Urszula reached the third round with a surprise 3-6, 6-4, 6-2 win against Serbia's Ana Ivanovic, a former French Open champion.

Her next opponent is Germany's Angelique Kerber, who ended Japanese No.1 Ayumi Morita's run with a 6-3, 6-4 win.