Azarenka triumphed last week in Beijing and she kept her streak going with a 6-1, 6-1 decision over Simona Halep.
Petra Martic will be Azarenka's quarterfinal opponent after outlasting Patricia Mayr-Achleitner 6-2, 3-6, 6-0.
Second-seeded Ana Ivanovic also reached the quarterfinals with a 6-4, 6-3 win over Andrea Petkovic. Ivanovic will next face Kirsten Flipkens, who was a 4-6, 6-1, 7-5 winner Thursday over Mallory Burdette.
The other quarterfinal matches will send Irina-Camelia Begu against Bethanie Mattek-Sands and Julia Goerges against Sofia Arvidsson.