MASON, OHIO - AUGUST 14: Yoshihito Nishioka of Japan returns a shot to Kei Nishikori of Japan during Day 5 of the Western and Southern Open at Lindner Family Tennis Center on August 14, 2019 in Mason, Ohio. (Photo by Rob Carr/Getty Images)
MASON, OHIO - AUGUST 14: Yoshihito Nishioka of Japan returns a shot to Kei Nishikori of Japan during Day 5 of the Western and Southern Open at Lindner Family Tennis Center on August 14, 2019 in Mason, Ohio. (Photo by Rob Carr/Getty Images)