Ana Ivanovic advances to Bank of the West quarters

Former top-ranked Ana Ivanovic advanced to her first Bank of the West quarter-finals, beating Canadian qualifier Carol Zhao 6-1, 6-1 on Thursday.

The 11th-ranked Serb, looking for her fourth title of the year, will face top-ranked Serena Williams on Friday.

Chinese-born Zhao appeared in her second WTA Tour event and gained her first career win at the level on Tuesday when Yanina Wickmeyer retired because of a viral infection.

Ivanovic had three aces and won 75 percent of her first-serve points.

In other matches, third-seeded Angelique Kerber beat Coco Vandeweghe, 7-6(4), 0-6, 6-2, and Garbine Muguruza topped Daniela Hantuchova, 6-4, 6-4.