MONTREAL, ON - AUGUST 13: John Isner of the USA serves against Nick Kyrgios of Australia during day four of the Rogers Cup at Uniprix Stadium on August 13, 2015 in Montreal, Quebec, Canada. (Photo by Minas Panagiotakis/Getty Images)
MONTREAL, ON - AUGUST 13: John Isner of the USA serves against Nick Kyrgios of Australia during day four of the Rogers Cup at Uniprix Stadium on August 13, 2015 in Montreal, Quebec, Canada. (Photo by Minas Panagiotakis/Getty Images)