Top-seeded Russian Anastasia Pavlyuchenkova highlighted the second-round winners Wednesday at the $220,000 Citi Open tennis event.
Pavlyuchenkova outlasted Hungarian Melinda Czink 6-2, 2-6, 6-3 on the hardcourts at the William H.G. FitzGerald Tennis Center. Pavlyuchenkova will meet Chinese Taipei's Kai-Chen Chang in the quarterfinals.
Americans Vania King and wild card Coco Vandeweghe also advanced, setting up a quarterfinal clash. A fourth-seeded King beat countrywoman Irina Falconi 6-2, 7-6 (7-5), while Vandeweghe, seeded seventh, topped French qualifier Aravane Rezai 6-2, 6-2.
Vandeweghe reached her first-ever WTA final in Stanford two weeks ago.
Canadian wild card Eugenie Bouchard rallied to beat eighth-seeded Belarusian Olga Govortsova 1-6, 6-0, 6-3. Bouchard will next face third-seeded American Sloane Stephens.
Qualifier Jana Cepelova advanced by handling Romanian Edina Gallovits-Hall 6-3, 6-4. Her quarterfinal opponent will be fellow Slovakian Magdalena Rybarikova, who moved on with a 6-3, 7-5 victory over Greece's Eleni Daniilidou.
Stephens and Chang were second-round winners on Tuesday.
The 2012 D.C. champion will collect $37,000.