Serena Williams and Maria Sharapova were both pushed to three sets but progressed at the Sony Open on Saturday.
Top-seed Williams defeated Caroline Garcia 6-4, 4-6, 6-4 at the WTA Premier event in Miami. Get more information here.
Sharapova, the fourth seed at Key Biscayne, Fla., got past Czech left-hander Lucie Safarova 6-4, 6-7 (7-9), 6-2.
Sharapova had match points in the second set tie-break but could not convert. Safarova's comeback was thwarted in the first game of the decider as Sharapova broke and never rescinded her advantage.
Safarova showed some resilience, though, saving a total of eight match points for the encounter before Sharapova finally won.
Venus Williams, Sloane Stephens, Varvara Lepchenko and Madison Keys were among America women scheduled to play third-round matches on Sunday.
Saturday results:
Angelique Kerber (5), Germany, defeated Tsvetana Pironkova, Bulgaria, 6-0, 6-2.
Petra Kvitova (8), Czech Republic, defeated Donna Vekic, Croatia, 6-3, 6-4.
Ekaterina Makarova (23), Russia, defeated Sara Errani (9), Italy, 6-3, 2-6, 6-4.
Ana Ivanovic (12), Serbia, defeated Flavia Pennetta (20), Italy, 6-4, 6-3.
Kirsten Flipkens (19), Belgium, defeated Sabine Lisicki (14), Germany, walkover.
Serena Williams (1), United States, defeated Caroline Garcia, France, 6-4, 4-6, 6-4.
Maria Sharapova (4), Russia, defeated Lucie Safarova (26), Czech Republic, 6-4, 6-7 (7), 6-2.
CoCo Vandeweghe, United States, defeated Sam Stosur (16), Australia, 5-7, 7-5, 7-5.
Sunday's matches:
Carolina Wozniacki vs. Sloane Stephens
Venus Williams vs. Casey Dellacqua
Varvara Lepchenko vs. Ajla Tomljanovic
Dominika Cibulkova vs. Alize Cornet
Agnieszka Radwanska vs. Elena Vesnina
Carla Suarez Navarro vs. Kaia Kanepi
Na Li vs. Madison Keys
Barbora Zahlavova Strycova vs. Elina Svitolina
Contributing: OmniSport