Tennis superstar Novak Djokovic joins GQ to reveal his 10 Essentials. The Serbian tennis player breaks down his daily essentials: from his Head tennis racket (“I string it quite tight compared to most of the other guys”) to his healing disc (“it creates an electromagnetic field around it”). Watch the full episode of GQ Sports’ 10 Essentials, as Novak Djokovic reveals 10 things he can’t live without.