Novak Djokovic has admitted that he was forced to play "unbelievably" well during his semi-final clash against Roger Federer at the Australian Open earlier today.

The world number one wrapped up the first two sets in under an hour and despite the fact that Federer was then able to get a set on the board, Djokovic eventually won through in two hours and 23 minutes.

"I played unbelievably in the first two sets but I needed to because Roger has been playing unbelievably and I knew he would be aggressive," the defending champion said during his post-match interview.

"It's important to always believe you can play your best and it's important your convictions are stronger than your doubts."

Djokovic has won each of the five previous Australian Open finals that he has contested.