QUEBEC CITY -- Third-seeded Mona Barthel of Germany advanced to the Bell Challenge semifinals Friday, beating sixth-seeded Barbora Zahlavova Strycova of the Czech Republic 6-3, 6-4.

Barthel will face Belgium's Kirsten Flipkens on Saturday. Flipkens led Anna Tatishvili 6-2, 3-0 when the Georgian player retired because of a back injury. In the first round, Flipkens beat top-seeded Dominika Cibulkova of Slovakia.  
In the other quarterfinals, French qualifier Kristina Mladenovic routed American Melanie Oudin 6-0, 6-1, and eighth-seeded Lucie Hradecka of the Czech Republic faced American qualifier Lauren Davis.