MADRID, SPAIN - MAY 6: Novak Djokovic from Sebia serves a ball while playing against Milos Raonic from Canada, during a Madrid Open tennis tournament match in Madrid, Spain, on May 6, 2016. (Photo by Burak Akbulut/Anadolu Agency/Getty Images)
MADRID, SPAIN - MAY 6: Novak Djokovic from Sebia serves a ball while playing against Milos Raonic from Canada, during a Madrid Open tennis tournament match in Madrid, Spain, on May 6, 2016. (Photo by Burak Akbulut/Anadolu Agency/Getty Images)