Seventh seed Klara Zakopalova was made to fight all the way for her place in the quarter-finals of the WTA Copa Sony Ericsson Colsanitas in Bogota by Mariya Koryttseva.
The Czech was dominated by her Ukrainian opponent in the first set but battled back to win 1-6 6-3 6-4 and set up a last-eight date with Colombia's Mariana Duque Marino, who edged past Ukraine's Kristina Antoniychuk 7-6 (7/3) 7-6 (12/10).
In Thursday's other second-round match in the Colombian capital, Frenchwoman Pauline Parmentier defeated home favourite Catalina Castano 6-2 6-4 to secure a quarter-final meeting with fifth-seeded German Angelique Kerber.
