Home favourite Alejandro Falla battled from a set down to claim a 3-6 6-2 6-3 win over top seed Janko Tipsarevic to reach the semi-finals of the Claro Open in Colombia.
The 29-year-old left-hander, who is hoping to secure his first ATP Tour title, dropped the opening set to the Serbian.
However, Tipsarevic's first-serve percentage dropped to 38 per cent in the second and Falla took full advantage.
Falla struggled with his own delivery in the decider but it did not prove fatal as he claimed a notable scalp to set up a meeting against Vasek Pospisil.
The Canadian rallied to beat Matteo Viola from Italy 3-6 6-3 6-2 and reach his first ATP Tour semi-final.
Second seed Kevin Anderson found playing in front of an intimidating atmosphere in Bogota much easier than Tipsarevic as he easily dispatched Colombia's Santiago Giraldo in straight sets.
The South African broke three times on his way to a 6-3 6-3 win in just over an hour and will next face big serving Ivo Karlovic.
The Croatian's trademark serve was in good shape as he produced 22 aces in a 7-6 (5) 7-6 (3) win over Adrian Mannarino of France, the fifth seed.