Iga Swiatek beat Czech 10th seed Marketa Vondrousova 7-6(3), 6-1 to reach the Cincinnati Open semi-finals on Friday, as Coco Gauff downed Italy's Jasmine Paolini 6-3, 6-2 and Aryna Sabalenka beat an ailing Tunisian fifth seed Ons Jabeur 7-5, 6-3.
World number one Swiatek, who raised her game at the key moments, broke the Wimbledon champion five times and saved four of six break points to seal victory in 91 minutes, in a clash between the last two Grand Slam winners.
"It wasn't easy to adjust to her spin because she's a lefty," French Open champion Swiatek said during her on-court interview.
"She really used that and her experience for sure but I really wanted to be determined and fight for every ball, and in the end this is what worked."
Vondrousova enjoyed an ideal start and dropped only three points on serve by the time she built a 5-3 lead and served for the set twice. But she was denied both times by Swiatek before the Pole ran away with the tiebreaker.
Swiatek found a higher gear in the second where she feasted on Vondrousova's serve and broke three times, including in the final game where she sealed the win with a forehand down the line that the Czech was unable to chase down.
Swiatek, who is using this event as a tune-up ahead of her title defense at the August 28-September 10 US Open, credited the adjustments she made in between sets for her ability to make quick work of Vondrousova in the second frame.
"I tried to learn from that first set, and in the second set I knew exactly what to do and I think that's why it was such a good performance," Swiatek said.
Swiatek, who has occupied top spot in the world rankings since April 2022, will next face American seventh seed Gauff, whom she has beaten in all seven of their previous meetings, including twice this year.
Gauff has yet to drop a set in Cincinnati and after going down an early break on Friday she found the momentum against Paolini, breaking the Italian in the third, fifth and ninth games of the first set.
Gauff, who picked up the biggest title of her career in Washington earlier this month, dropped her serve in the first game of the second set but quickly hit her stride to sweep the final six games of the brisk, one hour and 13-minute match.
The 19-year-old acknowledged that while she does not have a good track record against upcoming opponent Swiatek, she believes recent improvements to her game could yield better results.
"I do feel a lot more confident going into it tomorrow. But she's not an easy opponent to play, especially against me," she told reporters.
"I think I really just got to take it point by point and try to stay mentally engaged every ball."
Unseeded Czech Karolina Muchova needed just 11 minutes on court to reach the semis as compatriot Marie Bouzkova retired from their match with right leg strain while trailing 3-0.
Muchova now faces Belarusian second seed Sabalenka, whom she beat in the Roland Garros semi-final earlier this year.
Jabeur overcame Sabalenka en route to the Wimbledon final this year and their rematch had all the makings of an epic battle as they twice traded breaks in a tense first set before Sabalenka closed out the 12th game with a lethal backhand return.
Jabeur was up a break in the second set when the affair began to unravel, however, as the Tunisian took a medical timeout to have her right foot taped by a member of the tournament staff.
She bounded off her bench and jogged back onto the court but was clearly not herself anymore as she handed Sabalenka the break with a double fault in the sixth game and could not put up much of a fight as the Belarusian broke her again in the eighth.
"I'm super happy to be in the semi-finals again in Cincinnati, but right now I'm a little bit sad for Ons," the Australian Open winner said in on-court remarks.
"Fingers crossed - (Muchova is) a great player, we had really great battle at Roland Garros."
