David Ferrer into Mexico quarters
Also Wednesday, Gilles Simon (6) of France beat Donald Young of the United States 6-4, 6-3, Ukraine's Alexandr Dolgopolov downed Frenchman Jeremy Chardy 6-3, 6-4 and Croatia's Ivo Karlovic defeated Dudi Sela of Israel 7-6 (4), 6-2.
"I'm still struggling with my serve, but I got another win so I'm happy," Cibulkova said.
In other matches, No. 8 seeded Shuai Zhang of China beat Canada's Aleksandra Wozniak 6-1, 6-4; America's Christina McHale knocked out Kimiko Date-Krumm of Japan 7-5, 6-1; Croatia's Ajla Tomljanovic eliminated Victoria Duval of the United States 6-3, 6-0; and Frenchwoman Caroline Garcia downed Sharon Fichman of Canada 6-2, 7-5.