Top seed Mirjana Lucic-Baroni's purple patch continued as she reached another semi-final, while Kristina Mladenovic also advanced at the Abierto Mexicano Telcel.
Lucic-Baroni, 34, eased past unseeded Frenchwoman Pauline Parmentier in straight sets at the WTA International event on Thursday.
An Australian Open semi-finalist almost 18 years after her first grand-slam semi, the resurgent Lucic-Baroni powered past Parmentier 6-2 6-3 in Acapulco.
Lucic-Baroni fended off three break points and converted six of her own as the Croatian veteran progressed to a second successive semi-final after a little more than an hour, following on from her Melbourne Park exploits.
Awaiting Lucic-Baroni in the final four is seventh seed Lesia Tsurenko.
Ukraine's Tsurenko emerged triumphant 6-3 7-6 (7-5) against third seed Jelena Ostapenko, who was stung by a bee in the warm-up.
Mladenovic and Christina McHale will meet in the other semi-final.
French second seed Mladenovic accounted for Kirsten Flipkens 6-4 6-3, while fifth-seeded American McHale was too good for reigning Olympic gold medallist Monica Puig 6-2 6-2.