Iga Swiatek has won the French Open three times and the US Open onceWorld number one Iga Swiatek continued her US Open preparations with victory over Wimbledon champion Marketa Vondrousova at the Cincinnati Open.
The 22-year-old top seed overcame her Czech opponent 7-6 (7-3) 6-1 to reach the last four.
Swiatek will face American Coco Gauff or Italian Jasmine Paolini next.
The Pole, in her 72nd consecutive week at world number one, begins her title defence at Flushing Meadows on 28 August.
Following her last-16 win over China's Zheng Qinwen on Thursday, Swiatek called for an end to online abuse after she was criticised for dropping the first set.
Swiatek came from behind to progress against Zheng and was almost faced with the same challenge against Vondrousova as she trailed 5-3 in the opening set.
Vondrousova, 24, had not faced a break point until then but when serving for the set at 5-4 she hit two double faults before Swiatek broke her to love and then rallied to win the tie-break.
Four-time Grand Slam champion Swiatek then powered through the second set, breaking serve three times to reach her 10th semi-final of the year.
Vondrousova, who claimed a shock win at SW19 earlier this summer, was competing in her first WTA 1000 quarter-final in more than three years.
World number seven Gauff will face 43rd-ranked Paolini in the quarter-finals after the Italian's last-16 opponent Elena Rybakina retired because of injury.
Elsewhere in the last eight, Ons Jabeur plays world number two Aryna Sabalenka in a repeat of their Wimbledon semi-final, which Tunisia's Jabeur fought back to win.
