Top-ranked Victoria Azarenka eased into the third round of the Pan Pacific Open with a 6-1, 6-1 win over Austria's Tamira Paszek on Tuesday.
Two-time champion Maria Sharapova had a tougher time subduing British qualifier Heather Watson 6-7 (7), 6-3, 6-4, while 2011 Wimbledon champion Petra Kvitova, the fourth seed, was upset by Petra Martic of Croatia 6-4, 6-4.
Other winners included Grand Slam champions Li Na and Sam Stosur. Li defeated Anastasia Pavlyuchenkova of Russia 7-5, 4-6, 6-2, and Stosur overcame Francesca Schiavone 4-6, 6-2, 7-5.
Azarenka played her first match since losing a thriller in the U.S. Open final to Serena Williams. Next up will be Roberta Vinci of Italy, who beat qualifier Pauline Parmentier of France 6-3, 6-1.