Spanish hope Sara Sorribes Tormo posted a career-best result at the Mutua Madrid Open on Sunday, ousting former World No.1 Naomi Osaka 6-3, 6-1 in 1 hour and 28 minutes of play to reach the Round of 16.

Making her sixth main-draw appearance at the WTA 1000 event based in her nation's capital, World No.47 Sorribes Tormo will take her first trip into the sweet sixteen of the event.

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In the Round of 16, Sorribes Tormo will square off against Daria Kasatkina, who also notched a big win on Sunday with a 3-6, 6-3, 6-1 upset of No.4 seed Maria Sakkari.

Surging Spaniard: In the biggest Hologic WTA Tour event on Spanish soil, Sorribes Tormo continued her superb performance this fortnight. Sorribes Tormo started the week with an upset of Top 20 player Anastasia Pavlyuchenkova.

Playing the event for the first time without needing a wildcard to get into the field, Sorribes Tormo wore down four-time Grand Slam champion Osaka, who came into the match with her lower left leg heavily taped.

Sorribes Tormo now has an even 2-2 win-loss record against Osaka. The Spaniard had previously stunned Osaka at a Billie Jean King Cup qualifying tie in 2020, which also occurred on clay in Spain.

Sorribes Tormo is the only Spanish player remaining in the singles draw. No.2 seed Paula Badosa and No.7 seed Garbiñe Muguruza suffered upsets over the last two days.

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Match moments: An early flurry of three consecutive breaks left Sorribes Tormo standing with a 3-2 lead in the opening set. The Spaniard triumphed in numerous tricky points to retain her momentum through the rest of the opener and grasp the one-set lead.

A brief visit from the trainer at 3-0 in the second set was unable to help Osaka prevail over the fleet and gritty play of Sorribes Tormo, despite some signature rally winners by the former World No.1 down the stretch. 

All told, Sorribes Tormo's consistency and footspeed won out at key moments, as the Spaniard forced errors to convert five of her nine break points and sweep to victory.

Kasatkina stays perfect against Sakkari: Kasatkina took home a comeback victory over Sakkari after just under two hours of play to reach the Madrid Round of 16 for only the second time. Kasatkina was a Madrid quarterfinalist in 2018.

"The beginning was a bit shaky," Kasatkina said afterward. "In the end of the first set, I found my game and the ways to turn this match around. The score is not showing exactly how the match was going, but I’m happy that I could close the match and not spend a lot of time on the court."

Former Top 10 player Kasatkina came into the clash having won her three previous meetings with Sakkari, but they had not faced off since 2018. It appeared that World No.5 Sakkari might get her maiden win over Kasatkina after powering through the first set.

However, World No.23 Kasatkina held firm in the second set, and she made her move at 4-3, earning the only break of that set with well-timed rally forehands.

After serving out the second set to level the match, Kasatkina was mostly unbothered as she romped through the decider, improving to 4-0 against Sakkari.

Madrid: Kasatkina improves to 4-0 against Sakkari