A fatigued Novak Djokovic stared down a ferocious challenge from Rafa Nadal to defend his Australian Open title early on Monday in the longest grand slam final ever played.

The Serbian world number one, who defeated Nadal for the Wimbledon and US Open crowns last year, captured the decisive break at 5-5 in the fifth and in a frenzied atmosphere at Rod Laver Arena rode out a 5-7 6-4 6-2 6-7 7-5 winner.