World number ones Jannik Sinner and Iga Swiatek displayed resilience on Saturday, overcoming difficult matches to advance to the semi-finals of the ATP and WTA Cincinnati Open.

Sinner mounted a comeback against Andrey Rublev, avenging his loss to the Russian just a week earlier in Montreal. The Italian triumphed 4-6, 7-5, 6-4 after battling through challenging conditions. Sinner, who has recently struggled with injuries and illness, will now face third-ranked Alexander Zverev in the semi-finals. Zverev, the 2021 champion, also had to fight hard, defeating Ben Shelton 3-6, 7-6 (7/3), 7-5, despite rain delays in the final set.

Reflecting on his match, Zverev acknowledged the difficulties posed by the weather and Shelton's strong performance. "Conditions and the interruptions were tough, but Ben was the toughest part of the match," Zverev said.

Sinner, playing only his second match of the week after a first-round bye and a walkover, showed mental toughness in the face of windy conditions, securing victory with 31 winners, including 10 aces, while Rublev struggled with 47 unforced errors.

In the women's draw, Iga Swiatek also staged a comeback, defeating teenage sensation Mirra Andreeva 4-6, 6-3, 7-5 in a match that lasted over two and a half hours. Swiatek, who has been in dominant form this season, secured her 53rd win of the year and her 25th on hardcourt. She will face Aryna Sabalenka in the semi-finals, after the Belarusian defeated Liudmila Samsonova 6-3, 6-2.

Swiatek acknowledged the challenges posed by Andreeva and the conditions, stating, "It was a tight match. Every point matters at the end. It was not easy for sure."

Sabalenka, aiming for her first title since winning the Australian Open in January, was pleased with her straight-sets win. "I'm really happy to get this win in straight sets," she said.

In another women's quarter-final, American Jessica Pegula fought through fatigue and swirling winds to defeat Canada's Leylah Fernandez 7-5, 6-7 (1-7), 7-6 (7/3) after more than three hours on court. Pegula, who played two matches on Friday, admitted the effort was taxing but credited her determination for the victory.

"We had really tough conditions, the wind was really swirling, and we both had trouble on serve. It was crazy today but I got through," Pegula said.

The Cincinnati Open, serving as a key tune-up for the US Open, continues with the semi-finals on Sunday.