Roger Federer remains as dangerous as ever, warns wary Novak Djokovic

Novak Djokovic believes beating Roger Federer is as tough a task as it has ever been as the rivals prepare for another grand slam showdown at the Australian Open.

Djokovic and Federer will face off for the 45th time when they clash in the semi-finals in Melbourne after they came through their last eight matches on Tuesday. Djokovic eased past Kei Nishikori 6-3 6-2 6-4 while Federer beat Tomas Berdych 7-6 (7/4) 6-2 6-4.

The head-to-head between the pair currently lies firmly in the balance at 22 wins each but Djokovic has the edge in recent match-ups, winning their last three meetings in grand slams.