MONTREAL — Canadian teenager Victoria Mboko upset top-seeded Coco Gauff 6-1, 6-4 on Saturday night to reach the National Bank Open quarterfinals.
Gauff dropped to 2-3 since winning the French Open. She followed the major victory with opening losses in Berlin and Wimbledon, then overcame double-fault problems to win two three-set matches in Montreal. Gauff had five double-faults Saturday after having 23 in her opener against Danielle Collins and 14 against Veronika Kudermetova.
The 18-year-old Mboko, ranked 85th in the world, will face the winner of the late match between Lin Zhu of China and Jessica Bouzas Maneiro of Spain.
In Rome in May, Gauff rallied to beat Mboko 3-6, 6-2, 6-1 in a round-of-64 match.
Earlier, No. 24 seed Marta Kostyuk of Ukraine and No. 9 seed Elena Rybakina of Kazakhstan set up a quarterfinal match. Kostyuk beat McCartney Kessler of the United States 5-7, 6-3, 6-3, and Rybakina topped Dayana Yastremska of Ukraine 5-7, 6-2, 7-5.
