World 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.