Djokovic, who lost to Federer in the US Open final last year and beat him en route to the Australian Open title earlier this year, blamed his own fatigue for the lop-sided defeat.

The 21-year-old appeared listless early on against Federer after needing almost 10 hours to battle past his last three opponents, including a five-set win over Spaniard Tommy Robredo in the last 16 and a four-set tussle against Andy Roddick.