In a surprising turn of events at the WTA Canadian Open, reigning US Open champion Coco Gauff was defeated by Russia's Diana Shnaider 6-4, 6-1 in the third round on Friday. Shnaider, ranked 24th, claimed her first-ever victory against a top-10 player, knocking out world number two Gauff in a match that lasted just 70 minutes.

Shnaider, who is enjoying a breakthrough season with three WTA titles to her name already, capitalized on Gauff's unforced errors and windy conditions to secure the upset. The 20-year-old Russian now advances to her first WTA Masters level quarter-final, where she will face fellow Russian and sixth seed Liudmila Samsonova, who defeated Belgium's Elise Mertens 6-2, 6-4.

Gauff, who admitted to struggling with fatigue and mental exhaustion, was broken at crucial moments, including a double fault that handed Shnaider a decisive 3-1 lead in the second set. Despite the loss, Gauff remains focused on her upcoming title defense in Cincinnati, the final major event before the US Open.

Meanwhile, US third seed and defending champion Jessica Pegula continued her strong performance with a 6-2, 6-4 victory over fellow American Ashlyn Krueger. Pegula will face Peyton Stearns in the quarter-finals, after Stearns advanced when 12th seed Victoria Azarenka retired from their match.

The American contingent at the Canadian Open is further strengthened by an all-US quarter-final between eighth seed Emma Navarro and Taylor Townsend. Navarro overcame Ukraine's Marta Kostyuk 7-5, 7-5, while Townsend stunned Latvian fourth seed Jelena Ostapenko with a 6-2, 6-1 win.

In another high-profile match, two-time reigning Australian Open champion Aryna Sabalenka of Belarus dispatched Britain's Katie Boulter 6-3, 6-3. Sabalenka, the second seed, will meet American Amanda Anisimova in the quarter-finals.