MASON, OH - AUGUST 15: Juan Martin Del Potro of Argentina serves to Tomas Berdych of the Czech Republic during the Western and Southern Open on August 15, 2017 in Mason, Ohio. (Photo by Rob Carr/Getty Images)
MASON, OH - AUGUST 15: Juan Martin Del Potro of Argentina serves to Tomas Berdych of the Czech Republic during the Western and Southern Open on August 15, 2017 in Mason, Ohio. (Photo by Rob Carr/Getty Images)