Owing to his extroverted personality , fluency in several languages , and willingness to go along with comedic concepts , Djokovic became a fixture on entertainment-based TV talk shows around the globe immediately upon achieving a measure of prominence via results on the tennis court . After winning the Australian Open , his first major , in early 2008 , Djokovic appeared on the American late-night programme '' The Tonight Show with Jay Leno '' . In May 2008 , he was a special guest during the first semi-final of the Eurovision Song Contest , held in Belgrade that year . He threw a big tennis ball into the crowd , announcing the start of the voting and together with one of the show 's co-presenters , Željko Joksimović , Djokovic sang a song about Belgrade
Eurovision Song Contest
Eurovision Song Contest 2008
Novak Djokovic