Swiatek extended her match winning streak to 15 with a 6-4, 3-6, 7-5 victory over 17-year-old Mirra Andreeva. Swiatek will face third-ranked Arnya Sabalenka, a 6-3, 6-2 winner over 10th-ranked Liudmila Samsonova 6-3, 6-2.

Sinner avenged last week's loss to No. 6 Andrey Rublev in the quarterfinals in Montreal with a 4-6, 7-5, 6-4 victory to become the first Italian man to reach the Cincinnati semis in the Open era.

“It was very windy and I tried to be as consistent as possible,” Sinner said. “First time that I've played a semifinal in this place, so that's very positive.”

Swiatek and Sabalenka have met twice already this year, with Swiatek winning finals at Roland Garros and Madrid. Swiatek is 8-3 against the two-time Grand Slam winner.

“We're both players that kind of deserve to be in semifinals and finals, because we're working very hard," Swiatek said. "I respect Aryna so much. Physically, she's always fighting and has lots of power.”

Neither player has reached the final in Cincinnati.

Swiatek lost to eventual champion Coco Gauff last year in her first semifinal appearance. Sabalenka is a three-time semifinalist, including each of the past two years.

“We've had a lot of great battles in the past,” Sabalenka said. “It's always a high-intensity match. I'm really looking forward to another great battle against her.”

Sinner will face No. 3 Alexander Zverev. Zverev, the only remaining former champion in the draw, beat Ben Shelton 3-6, 7-6, 7-5. Zverev has won four straight against Sinner.

Frances Tiafoe advanced to the semifinals for the second consecutive year when Hubert Hurkacz retired in the second set because of a calf injury. Tiafoe will face the winner of the late match between Holger Rune and Jack Draper.

In the other women's quarterfinals, No. 6 Jessica Pegula outlasted Leylah Fernandez, 6-2, 6-7, 7-6 for her first semifinal berth in Cincinnati. Pegula, coming off a successful title defense Monday in Canada, will face Paula Badosa.

Badosa beat Anastasia Pavlyuchenkova 6-3, 6-2. 

“Paula is really playing some good tennis," Pegula said. "She turned her year around and is finding some form. She's a top player."