Gauff defeats Osaka at the Silicon Valley Classic

Coco Gauff was too sharp with her return game for Naomi Osaka in the second round of the Silicon Valley Classic on Thursday, coming away with a 6-4 6-4 win.

Gauff – the world number 11 and tournament's sixth seed – created 12 break point opportunities in the match, while only allowing one for Osaka, despite eight double-faults.

Ultimately, Gauff won 41 per cent (29-of-71) of the points off Osaka's serve, while converting 85 per cent (28-of-33) of her successful first serves into points.

Earlier in the day in a major upset, top seed Maria Sakkari was eliminated in straight sets 6-1 6-3 by American Shelby Rogers. 

The world number three struggled with her serve throughout, landing only 45 per cent of her first serves, and winning just 52 per cent (12-of-23) of those points.

World number six Aryna Sabalenka needed three sets to defeat unseeded American Carolina Dolehide 5-7 6-1 7-5, and Russia's Veronika Kudermetova had less trouble dispatching Claire Liu 6-2 7-5 to set up an exciting match with Ons Jabeur in the quarter-final.

Meanwhile, in Washington at the Citi Open, Emma Raducanu played in the longest two-set match of the WTA season, defeating Camila Osorio 7-6 (7-5) 7-6 (7-4) in two hours and 49 minutes.

Both women created at least a dozen break point opportunities, with four total breaks each as the young British star battled blisters on her hands.

Raducanu will play Liudmila Samsonova after the Russian eliminated Australia's Ajla Tomljanovich 4-6 6-3 6-2.

In the last match of the day, China's Xiyu Wang got the better of Croatia's Donna Vekic 4-6 7-5 6-1, and she will meet the winner between Tereza Martincova and Victoria Azarenka in the quarter-final.