Second-seeded Kei Nishikori moved into his 11th ATP quarterfinal of the season by beating 16th-seeded Leonardo Mayer, 6-4, 6-4, at the Citi Open in Washington. Nishikori will next meet Sam Groth, who delivered 20 aces in a 6-3, 6-4 victory over seventh-seeded Feliciano Lopez.
Third-seeded Marin Cilic, getting his hardcourt game in gear a few weeks before defending his United States Open title, also advanced to the quarterfinals with a 7-6 (2), 7-6 (3) victory over 13th-seeded Sam Querrey.
u25a0 Agnieszka Radwanska beat the qualifier Misaki Doi, 1-6, 6-2, 6-0, in the second round of the Bank of the West Classic in Stanford, Calif.