Novak Djokovic overcame a second-set wobble to ease past Tomas Berdych 6-1 4-6 6-1 6-4 in their Australian Open quarter-final today.

The Serb showed no signs of fatigue from his five-hour battle with Stanislas Wawrinka in the early going, quickly securing a double break to claim the first set in 28 minutes.

Berdych battled back in the second and used a succession of huge forehand winners to earn a vital break of serve.

Djokovic had two break points of his own to save the set but could not take advantage as the Czech levelled the match.

From the third set on Djokovic took complete control, forcing a string of unforced errors from Berdych, who tightened up on serve and struggled to keep the ball in play on crucial points.

Berdych went a break down early in the fourth and despite fighting on with a back problem could not find a way to respond.

Djokovic served out the match with ruthless efficiency to advance to the last four, where he will face Spanish battler David Ferrer.