Novak Djokovic wary of Gilles Muller challenge

Novak Djokovic has admitted that it will be challenge for him to face Gilles Muller for the first time in their fourth-round clash at the Australian Open.

The world number one eased into the last 16 of the competition with a straight-sets win over Fernando Verdasco, setting up the match against the unseeded 31-year-old.

However, Djokovic is adamant that he will have to be clinical in his preparation for the match as never before played Muller in his career.

He told reporters: "That's something that is obviously a challenge for me, to come to the court and play the way I want to play against somebody I never played against before.

"That can be also dangerous because of the uncertainty of what he's going to do in some moments."

Muller knocked out American John Isner to book his date with the world number one.