David Ferrer has admitted that he will have to find a new level of performance to overcome Novak Djokovic if the pair meet in the semi-finals of the Australian Open later this week.

The Spaniard came from two sets down to beat Nicolas Almagro 6-4 6-4 5-7 [4]6-7 2-6 in today's first quarter-final thanks to a spirited fightback.

Djokovic or Tomas Berdych await Ferrer in the final four but he has insisted that he will relish the chance to test himself against the defending champion should he progress.

He told reporters: "Nole is a special player, he has every shot. Finally in the fifth set, Djokovic was better physically than Wawrinka and I think he will be recovered, for sure, because he is physically unbelievable.

"He's the best, I think. He's the number one of the world and the favourite to win the Australian Open for me.

"I will see the match tonight [with Berdych]. But anyway I will have to play better than today for to win, for sure."

Ferrer has a poor record against the Serb, winning just four of their 14 matches and losing all four times they have met in a Grand Slam.