The second-seeded Ivanovic took just 54 minutes to zip by Czech Petra Cetkovska 6-0, 6-0.
Jankovic won her match against 14th-seeded Agnieszka Radwanska of Poland 6-3 7-6 (7-3).
"It was much tougher than it looked or the results indicate," Ivanovic said. "I worked hard and I played almost without mistakes. Obviously at some point you think about the score and might think you can relax a little bit, but that was not the case."
She broke her inexperienced foe six times and overpowered her with unrelenting forehand and backhand shots.
All women's matches Sunday were fourth-rounders.
In the quarterfinals, Ivanovic faces Schnyder and Jankovic plays Navarro.