Renata Zarazua became the first Mexican woman to reach a WTA Tour semi-final since 1993 after continuing her fairytale run at the Mexican Open.
Local wildcard Zarazua upstaged Tamara Zidansek 6-2 3-6 6-2 en route to the final four of the WTA International tournament in Acapulco on Thursday.
World number 270 Zarazua, 22, will face teenage qualifier Leylah Fernandez for a spot in the final.
Canadian 17-year-old Fernandez moved through to her maiden WTA semi-final after ousting fellow teen Anastasia Potapova 6-3 7-5.
Elsewhere, seventh seed Heather Watson prevailed 6-3 1-6 6-1 against American Christina McHale.
Next up for Watson is Wang Xiyu, who eased past sixth seed Zhu Lin 6-2 6-2.