Johanna Larsson and Lara Arruabarrena each overcame scares to reach round two of the Copa Colsanitas on Monday.
Third seed Larsson surprisingly lost the first set of her match against Belgian-born French youngster Fiona Ferro, a player 158 places below her in the WTA rankings.
However, Ferro was unable to capitalise on her strong start as Larsson hit back emphatically to triumph 2-6 6-2 6-1 in Bogota.
Arruabarrena, the fourth seed for this clay-court event and the champion in 2012, also needed to come from a set down in a 4-6 6-3 6-2 win over qualifier Conny Perrin.
Cindy Burger of the Netherlands was another winner in three sets, dumping out the higher-ranked Tatjana Maria.
Burger will face compatriot Kiki Bertens in the second round, providing the top seed gets past Nina Stojanovic on Tuesday.
Monday's other first-round matches brought wins for Aleksandra Krunic, Sachia Vickery and Elitsa Kostova.