Victoria Mboko, just 18 and ranked No. 85, stunned No. 1 seed Coco Gauff in straight sets to become the youngest Canadian quarterfinalist at the Omnium Banque Nationale in nearly four decades.

Gauff has dropped to 2-3 since winning Roland Garros, following up the major victory with opening losses in Berlin and Wimbledon.

Victoria Mboko's stellar run at the National Bank Open hit a new level Saturday. The Canadian rolled to a 6-1, 6-4 victory over No. 1 seed Coco Gauff of the United States, winning the women's singles ...