Novak Djokovic's legendary fitness to be tested in match with David Ferrer

Defending champion Novak Djokovic will face another test of his extraordinary fitness when he takes on Spanish terrier David Ferrer for a place in the Australian Open final today.

The Serbian world No 1 has looked the player to beat so far with an epic five-set, five-hour victory over Stanislas Wawrinka and an untroubled dismissal of fifth seed Tomas Berdych in the quarter-finals.

Now comes a war of attrition with the relentless Ferrer, whose never-say-die attitude will again test Djokovic's stamina in an expected long, drawn-out night semi-final on Rod Laver Arena.

Ferrer, the fourth seed in Melbourne this year in the absence of celebrated countryman Rafael Nadal, modestly baulks at talk that he belongs to the exclusive group alongside Djokovic, Roger Federer and Andy Murray.

He declares Djokovic is the best, raising questions about whether he has the self-belief that he can deny the top seed his expected place in Sunday's final.

"Nole [Djokovic], he's a special player. He has all the shots. He's the best, I think," said Ferrer.