Russia’s Anna Kalinskaya came through at the crucial moments while beating second-seeded Madison Keys of the United States 6-2, 6-4 on Thursday in the third round of the Credit One Charleston (S.C.) Open.

Kalinskaya took advantage of four of her five break-point opportunities, and she saved seven of Keys’ eight break points.

In the quarterfinals, Kalinskaya will oppose another U.S. player, Sofia Kenin, who topped fifth-seeded Daria Kasatkina of Australia 6-3, 7-6 (7).

Top-seeded Jessica Pegula eased into the quarterfinals with a 6-3, 6-2 win over Australia’s Ajla Tomljanovic. Fourth-seeded Emma Navarro won an all-U.S. matchup against 15th-seeded Ashlyn Krueger, 4-6, 6-4, 6-2.

Also moving into the quarterfinals were third-seeded Qinwen Zheng of China, seventh-seeded Danielle Collins and eighth-seeded Amanda Anisimova, both of the United States, and ninth-seeded Russian Ekaterina Alexandrova.

Copa Colsanitas Zurich

Second-seeded Camila Osorio of Colombia overcame a slow start to defeat Emina Bektas of the United States 1-6, 7-6 (5), 6-2 in the second round at Bogota, Colombia.

Bektas, a 32-year-old who is ranked 186th in the world, had a match point at 4-5 in the second set before Osorio rallied.

Osorio’s quarterfinal opponent will be sixth-seeded Tatjana Maria of Germany, who downed the United States’ Hanna Chang 6-0, 7-6 (0).

Croatia’s Lea Boskovic upset eighth-seeded Cristina Bucsa of Spain 6-1, 6-4, and Argentina’s Julia Riera eliminated the Unites States’ Iva Jovic 6-4, 6-2.

–Field Level Media