Fifth-seeded Agnieszka Radwanska breezed past Barbora Zahlavova Strycova 6-1, 6-2 in the opening round of the Bank of the West Classic on Monday.
Poland's Radwanska is seeking her first WTA title in three years, but is enjoying a solid season. She reached the quarterfinals of the Australian Open and the fourth round of the French Open.
Monday's win put her into the round-of-16 and remained on track for a likely clash with fourth-seeded Samantha Stosur in the quarterfinals. Victoria Azarenka and Maria Sharapova are the top two seeds and received byes to the second round, as did third-seeded Marion Bartoli and Stosur.
Dominika Cibulkova won through to the last 16 with a 6-2, 7-6 (7) win over Japanese veteran Kimiko Date-Krumm.
The Slovak was making her first appearance on tour since reaching the quarterfinals in Wimbledon. She has not lost more than two matches in a row all season.
American Christina McHale beat Croatia's Mirjana Lucic 6-1, 6-0 and will next meet Cibulkova.
Canadian Rebecca Marino topped American Coco Vandeweghe 6-4, 6-4 in another match. She'll play Bartoli in the second round.