
Serbia's Novak Djokovic celebrates after winning a point against Spain's Albert Ramos-Vinolas during their Davis Cup quarterfinal tennis match in Belgrade on April 7, 2017. (Xinhua/Predrag Milosavljevic)
 
Serbia's Novak Djokovic celebrates after winning a point against Spain's Albert Ramos-Vinolas during their Davis Cup quarterfinal tennis match in Belgrade on April 7, 2017. (Xinhua/Predrag Milosavljevic)