No. 1 seed of Iga Swiatek of Poland battled back to avoid an upset on Saturday, capturing a 4-6, 6-3, 7-5 victory over Russian Mirra Andreeva in the quarterfinals of the Cincinnati Open in Mason, Ohio.

It looked like Andreeva was going to pull off a stunning win when she went up 5-4 in the third set, but Swiatek, the World No. 1, took the next three games to end the 17-year-old’s historic run at the tournament.

Andreeva was just the fourth player under the age of 18 to reach the quarterfinals of a WTA-1000 level event since 2009, the year that tournament tier was introduced.

“She’s playing and behaving like she’s older,” Swiatek said of Andreeva. “We were playing even, at a similar level, so it was really tight and every point mattered at the end. … I’m happy that I just did solid, and yeah. It wasn’t easy, for sure.”

Swiatek prevailed despite converting only 2 of 10 break points and having fewer aces (12-6). She will go up against Belarus’ Aryna Sabalenka, the No. 3 seed, in the semifinals.

Sabalenka was a 6-3, 6-2 winner over 10th-seeded Russian Liudmila Samsonova on Saturday, swatting five aces against zero double faults. She saved 3 of 3 break points and won 27 of 34 first-serve points.

It took Sabalenka just 79 minutes to oust Samsonova.

Two more quarterfinal matches were scheduled for Saturday. No. 6 seed Jessica Pegula of the United States was set to face Canadian Leylah Fernandez before Anastasia Pavlyuchenkova of Russia and Spain’s Paula Badosa squared off in the nightcap.

–Field Level Media