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NEW YORK, NEW YORK - AUGUST 30: Kei Nishikori of Japan returns a shot during his Men's Singles third round match against Alex de Minaur of Australia on day five of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 30, 2019 in Queens borough of New York City. (Photo by Steven Ryan/Getty Images)

NEW YORK, NEW YORK - AUGUST 30: Kei Nishikori of Japan returns a shot during his Men's Singles third round match against Alex de Minaur of Australia on day five of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 30, 2019 in Queens borough of New York City. (Photo by Steven Ryan/Getty Images)