NEW YORK, NY - SEPTEMBER 01: Kiki Bertens of the Netherlands returns the ball during her women's singles third round match against Marketa Vondrousova of Czech Republic on Day Six of the 2018 US Open at the USTA Billie Jean King National Tennis Center on September 1, 2018 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Al Bello/Getty Images)
