Gilles Muller was hardly disgraced as Serbian world number one Novak Djokovic showed his class when it mattered most in a 6-4 7-5 7-5 win on Monday.

Competing in his first fourth-round match at the Australian Open, Muller was not overawed by the occasion on Rod Laver Arena as the 31-year-old hit 47 winners.

However, Djokovic's superior quality shone through, with the four-time Australian Open champion limiting his unforced errors to 16 compared with Muller's 32 after a little more than two hours on court.

Djokovic " into his eighth successive quarter-final at the event " will now face eighth seed Milos Raonic for a place in the semis having not dropped a set.

Muller had battled hard to keep pace with Djokovic before the world number one stepped it up a gear to go up a break in the seventh game.

That is all Djokovic needed as he closed out the opening set to love in 32 minutes.

The second set followed a similar script, with Muller's serve causing Djokovic plenty of problems.

Posting a 79 per cent success rate on his first serve, the powerful left-hander from Luxembourg went neck-and-neck against Djokovic through 10 games.

Djokovic eventually claimed the pivotal break for a 6-5 lead and he went on to claim a two-sets-to-love cushion, despite both players hitting 12 winners apiece.

Muller refused to go away in the third set and he earned four break points in the fifth game, but Djokovic saved all of them.

Djokovic registered three double faults in an uncharacteristic set for the Serb, who struggled to close out the match.

But he was not to be denied as he finally broke in the 11th game for a 6-5 lead at the third time of asking before serving out to secure victory.