Iga Swiatek defeats Wimbledon champ Marketa Vondrousova in Cincinnati

Swiatek, the French Open champion, had trailed Vondrousova 5-4 in the opening set, but rallied to break back at 5-5 - only for both players to lose their next service games which brought up a tie-break.

Having taken that 7-3 with two more crucial mini-breaks, Swiatek maintained her momentum in the second set.

An early break and hold saw Swiatek lead 2-0 and she never relinquished control, closing out the match with two more breaks to complete the turnaround in one hour and 33 minutes.

"At the beginning, it wasn't easy to get used to her lefty spin, but I'm happy that I kind of played better and better throughout the whole match. At the end, I was really solid," the Pole said on the WTA Tour website.

"I made good decisions and chose the right solutions to win these points. I think she also kind of made some mistakes. The most important (thing) is to use your opportunity and I'm happy that I did that."

Swiatek goes on to face Coco Gauff after the American eased past Italian qualifier Jasmine Paolini 6-3 6-2.

The 19-year-old will be hoping to make the most of the support of the home crowd when she faces the world number one - having not taken a set off Swiatek in their past seven meetings.

French Open runner-up Karolina Muchova also advanced to the semi-finals after Marie Bouzkova was forced to retire following three games of their match.

She will meet Aryna Sabalenka in the final four, after the second seed endured a back-and-forth affair to eclipse fifth seed Ons Jabeur 7-5 6-3.

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