The top seed, who was sidelined with a wrist injury, controlled the 90-minute match throughout and set up a quarter-final meeting with another German, Sandra Kloesel.
Kloesel, ranked 119th in the world, beat seventh-seed Australian Samantha Stosur 7-6, 2-6, 6-3.
However, there was disappointment for Clijsters's Belgian compatriot Caroline Maes, who was beaten by Michaela Krajicek of the Netherlands 7-6, 2-6, 6-3.
The Dutch player will next face Serbian three seed, Ana Ivanovic who also had a tough time before beating Angelique Kerber of Germany 6-3, 7-6, 6-3.
Second seed Francesca Schiavone of Italy booked her spot in the last eight with a convincing 6-3, 6-4 victory over Poland's Agnieszka Radwanska.
The Italian will next take on Kaia Kanepi after the Estonian overcame Eleni Daniilidou of Greece 6-3, 6-4.
