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.

I just would like to serve how I do in doubles!” the American said. We talked to a leading mental coach about the 'weird'—but not uncommon—phenomenon.

Former three-time Grand Slam champion Lindsay Davenport says it is "unbelievable" that Coco Gauff has been winning matches in ...