The fourth-ranked Serb broke her opponent five times and was dominant on her service game on the outdoor clay. Jankovic will next face Italian player Roberta Vinci on Friday.
Klara Zakopalova, who upset top-ranked Venus Williams in the first round, beat Renata Voracova 7-6 (7), 5-7, 6-0. The 95th-ranked Czech will face fifth-seeded Carla Suarez Navarro in the quarterfinals. Navarro defeated Ekaterina Ivanova 0-6, 6-3, 6-0.
Also, sixth-seeded Sara Errani of Italy beat Polona Hercog of Slovenia 6-0, 7-6 (7) and third-seeded Kaia Kanepi of Estonia defeated Arantxa Rus of the Netherlands 7-5, 6-2.
Montanes, Ferrero, Gil reach Casablanca quarters
Petrova beats 14-year-old Keys at Ponte Vedra
