MASON, OHIO - AUGUST 14: Stefanos Tsitsipas of Greece returns a shot to Jan-Lennard Struff of Germany 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: Stefanos Tsitsipas of Greece returns a shot to Jan-Lennard Struff of Germany 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)