The Russian third seed won the first set but began to struggle with pain in her left hip and eventually decided to concede the match while trailing 4-6 6-2 4-1.
Spain's Cabeza Candela will tackle Monica Niculescu in the quarter-finals after the Romanian defeated German sixth seed Mona Barthel 7-6 (7/5) 6-1.
Also through to the last eight are top seed Samantha Stosur, who needed to save two match points to beat plucky Kristina Mladenovic 6-4 2-6 7-6 (9/7), and seventh seed Klara Zakopalova.
The Czech made light work of Zhang Shuai 6-1 6-2 and next meets Alison Riske, while Bojana Jovanovski stands between Stosur and a place in the semi-final.
Number two seed Kirsten Flpikens needed a third set tie-break to defeat wild card Storm Sanders.
The Australian won the first set 6-4 but the Belgian won the next two on tie-breaks, 7-6 (7/3) and 7-6 (7/5).
Qualifier Garbine Muguruza reached the next stage when her German opponent Yanina Wickmayer retired with the Spaniard leading 4-1 in the opening set.