Jankovic, coming off a strong run at the French Open, defeated Arantxa Rus 6-4, 6-2 with six breaks and then beat Johanna Larsson 6-2, 6-0 in 52 minutes. Jankovic won 76 percent of the points on serve versus Larsson, losing nine points in seven games serving.
Polona Hercog beat Zakopalova, the No. 2 seed, 6-3, 4-6, 6-1 with six breaks in a first-round match. She lost only six points on serve in the decisive third set.
Galina Voskoboeva eliminated Cornet, seeded third, 2-6, 6-3, 6-3 despite losing her serve twice in each set. She cashed in seven of her eight break opportunities in the second and third sets.
Andrea Petkovic came away a 6-1, 7-5 winner over the fourth-seeded Goerges. Petkovic took 55 percent of the points when receiving serve.
The Cornet and Goerges losses came in the second round,
In first-round action, seventh-seeded Simona Halep beat Grace Min 6-0, 7-5 and Estrella Cabeza Candela got past Tereza Martincova 6-2, 6-3. Halep came back and defeated Cabeza Candela 6-1, 6-4 in their second-round meeting.
Fifth-seeded Lucie Safarova swept past Maria-Teresa Torro-Flor 6-4, 6-2 while No. 8-seeded Annika Beck was a 6-4, 6-2 winner over Karin Knapp and Hercog advanced to the quarterfinals with a 6-3, 6-3 win over Julia Cohen.