Facing Roger Federer is something Andy Murray will never take for granted.

The pair will meet for the 21st time in the quarter-finals of the Australian Open on Wednesday, with Murray looking to extend his head-to-head lead to 12-9.

Asked if there was still something special about playing Federer, the Scot said: "I think there's always going to be because of everything that he's achieved in the game.

"Whenever Roger finishes, or Rafa (Nadal), I am not going to play against guys that have won 17, 14, 15 slams, however many Rafa has won, however many he'll go on to win.

"So it's always going to be special playing against him."

Federer is looking for his 18th grand slam title, and the chances of him achieving that looked remote at best until he demolished Jo-Wilfried Tsonga in the fourth round.

It was a vintage performance from Federer, who appears to have recovered from back problems that heavily contributed to his struggles in 2013.

This will be his first match against Murray since they met in the semi-finals here 12 months ago, a clash the Scot won in five sets for his first grand slam victory over the Swiss, who has beaten him in three slam finals.

"I've played him 20 times I think," said Murray. "So all of those matches, it's all experience. You know how you need to play against him, tactically things that work and things that don't work.

"Obviously last year is pretty relevant because it's on the same court and it will be under the same conditions. But in an individual sport, any day is a new day. Anything can happen.

"You play 10 per cent below your best, you can be off the court quickly. So whether my tactics are great or not, I need to play a great match to win."

The clash will also be the first meeting between two of the super coaches, with Murray's mentor Ivan Lendl coming up against his former 1980s rival Stefan Edberg.

Edberg has committed to working with Federer for at least 10 weeks this year, and commentators were quick to put two and two together when the Swiss showed a particular willingness to charge to the net against Tsonga.

Murray said: "You would assume that's something that Edberg would be able to help with. He was pretty good at that.

"But at the same time, they've been working together for a week. You'll see how much the coaches have helped the players and the things they've been working on in three, four, five months' time."

Murray's route to the last eight has been unusual, with the Scot beating three players ranked outside the top 100 as well as familiar foe Feliciano Lopez.

Murray's first blip came on Monday when he dropped the third set to Stephane Robert having held four match points but he quickly recovered.

The lack of high-class opponents means there is still a certain unknown factor about Murray's level following back surgery in September.

This will be only his seventh competitive match since then, but Lendl does not believe it will be an issue.

He told the BBC: "I think Andy's ready to go toe to toe with these guys but even if you're really ready and you haven't had any setbacks or injuries to come back from, you still never know what's going to happen.

"He still could lose the match easily. But Andy had a good (training) block in Miami, he has played enough matches now, so none of that is an issue."

Former Wimbledon champion Goran Ivanisevic agrees, the Croatian saying: "He's recovered well. He wouldn't be here if he hadn't recovered.

"He hits the ball very good, he plays well, he moves well, and he is ready. He thinks he can win the tournament."

Ivanisevic added of Federer: "Roger Federer is like a magician and magicians always have some tricks in their pockets. I hope he pulls out some tricks, I love to watch Roger.

"Stefan is going to push him to be more aggressive but now he faces Andy, who is one of the best returners in the game, the guy passes you unbelievably.

"If you don't come on the perfect ball, you're going to be passed. But when Roger still wants to be on the court, he's always going to be dangerous."