Novak Djokovic was dragged into a dogfight by talented teenager Dino Prizmic and had to dig deep to open his Australian Open title defence with a 6-2, 6-7(5), 6-3, 6-4 victory in the first round on Sunday. The Serbian, who played his first Australian Open a few months before the Croatian qualifier was born in August 2005, initially looked fully in control of the contest on the Rod Laver Arena court where he has won 10 of his 24 Grand Slam titles.