Pablo Carreno Busta fought from a set and a break down against Santiago Giraldo to set up an all-Spanish semi-final with top seed Feliciano Lopez at the Abierto Mexicano Los Cabos.
In a match that lasted over three hours in the Los Cabos heat, Carreno Busta ran out a 6-7 (4-7) 7-6 (7-2) 6-3 winner.
The world number 55 trailed 3-1 in the second set but eked out two break points in game five, taking the second before dominating Giraldo's serve in the tie-break.
Carreno Busta required seven break points to take the advantage in the decider and immediately hit back after suffering two breaks to reach the final four.
His opponent will be Lopez, who comfortably saw off world number 361 Julien Benneteau 6-3 6-4, avenging the defeat suffered at the Frenchman's hands at Indian Wells this year.
The other semi-final sees pits Ivo Karlovic against Dusan Lajovic.
Karlovic overcame Marcel Granollers 2-6 7-6 (7-3) 6-1, while Lajovic edged out Nicolas Almagro 7-5 7-6 (7-5).