TORONTO, ON - JULY 27: Novak Djokovic of Serbia plays a shot against Gilles Muller of Luxembourg on Day 3 of the Rogers Cup at the Aviva Centre on July 27, 2016 in Toronto, Ontario, Canada. (Photo by Vaughn Ridley/Getty Images)
TORONTO, ON - JULY 27: Novak Djokovic of Serbia plays a shot against Gilles Muller of Luxembourg on Day 3 of the Rogers Cup at the Aviva Centre on July 27, 2016 in Toronto, Ontario, Canada. (Photo by Vaughn Ridley/Getty Images)