World number one Iga Swiatek fought back from a set down to beat Qinwen Zheng 3-6 6-1 6-1 and reach the quarter-finals of the Western and Southern Open in Cincinnati, where she will face Wimbledon champion Marketa Vondrousova.
Zheng, who beat Venus Williams in the last round, threatened an upset as she opened up a 3-0 lead before taking the first set as Swiatek paid the price for 23 unforced errors.
