Top seed Jelana Jankovic moved a step closer to defending her Claro Open Colsanitas title as she advanced to the semi-finals with a 6-4 6-4 win over Lara Arruabarrena.
The Serbian, whose recent resurgence began in Colombia last year, saw off the Spanish qualifer in an hour and 22 minutes.
She will face Chanelle Scheepers in the last-four after the South African overcame eighth seed Lourdes Dominguez Lino 6-2 6-1.
"Lara is a hard player to play against - she has a lot of spin and variety in her game, so I just had to work the points as much as I could," Jankovic told the WTA's official website.
"I don't think I played that great today, but I was just trying to put as many balls in the court as possible and just hang in there. So that's it."
She added of the upcoming clash with Scheepers: "We haven't played in a while. She's a very tough opponent and is playing quite well lately, so it will be a good match. Hopefully I can play some good tennis and get back to the finals."
Fifth seed Caroline Garcia moved through after a fairly straightforward 6-1 7-5 win over Romina Oprandi, while her next opponent, Vania King, had to battle hard to beat home favourite Mariana Duque-Marino 7-6 (7-4) 7-5.