Top-seeded Angelique Kerber and third-seeded Maria Kirilenko each earned three-set victories in their second-round matches Thursday at the $235,000 Monterrey Open.
Kerber outlasted Alla Kudryavtseva of Russia, 6-4, 4-6, 6-2, as the German earned four breaks of serve in the third and deciding set.
Kirilenko was taken the distance by Serb Jovana Jaksic before the Russian pulled out a 6-0, 4-6, 6-1 victory on the hardcourts at Sierra Madre Tennis Club.
Lauren Davis upended fellow American Coco Vandeweghe in Thursday's other second-round match. Vandeweghe ousted second-seeded Marion Bartoli in the first round and saved four match points Thursday before falling, 6-4, 7-6 (10-8), in just under two hours.
This week's Monterrey champ will collect $40,000.