Tokyo: Two-time champion Maria Sharapova advanced to the third round of the Pan Pacific Open by beating British qualifier Heather Watson 6-7 (7), 6-3, 6-4 on Tuesday.
The seventh-seeded Li Na and fifth-seeded Angelique Kerber also won, but 2011 Wimbledon champion Petra Kvitova, the fourth seed, was upset by Petra Martic of Croatia 6-4, 6-4.
Top-ranked Victoria Azarenka faced Tamira Paszek of Austria late Tuesday, as did former No. 1 Caroline Wozniacki against Daniela Hantuchova.
Watson pushed Sharapova to three sets in their last match at the 2011 U.S. Open, and did it again by winning a marathon tiebreaker in the first set.
The second-seeded Sharapova, who won here in 2005 and 2009, took control of the third set when she broke Watson's serve for 4-3. She sealed the win when Watson sent a forehand return long.
Li defeated Anastasia Pavlyuchenkova of Russia 7-5, 4-6, 6-2, and awaited Wozniacki or Hantuchova, while Kerber of Germany downed Ayumi Morita of Japan 6-3, 6-4.
Also through were Marion Bartoli of France and Nadine Petrova of Russia.