Novak Djokovic is expecting his toughest assignment yet in Melbourne as he prepares for a semi-final showdown with Andy Murray at the Australian Open.

34079 - Djokovic wary of 'eager' Murray

The defending champion, who defeated Murray in last year's final, came through his quarter-final match with David Ferrer in straight sets but was made to work hard by the Spaniard for the first two hours en route to a 6-4 7-6 6-1 victory.

And the world No. 1 expects no let-up when he takes to the Rod Laver Arena on Friday at 8.30am.

"I'm going to try to keep the same game as last year I guess," he joked when asked about his gameplan for Murray, who breezed to a 6-3 6-3 6-1 victory against Japan's Kei Nishikori.

"No, I'm going to need more than that. Andy's playing great, he's in great shape with Ivan Lendl by his side - you can feel that he is physically fit and eager to win his first grand slam."

Meanwhile the Serbian is looking forward to a well-earned rest and the chance to watch Roger Federer and Rafael Nadal face off in the first semi-final on Thursday.

"I will enjoy it from my couch," Djokovic said. "They are two out of the four or five greatest players to play this game, they are so dominant and every time they play against each other is a treat for us players, so I'm going to have a nice dinner and just enjoy it.

"It's the top four players again in the last four of a grand slam - it's great for the tournament. Hopefully we can have a packed house and perform the best possible tennis."