Only Marin Cilic stands between Roger Federer and a 20th Grand Slam title as an injury-ravaged Australian Open staggers to its Sunday final at Melbourne Park.

The 36-year-old Swiss marvel continues to defy the years and attrition rate to reach his 30th Grand Slam decider and a shot at his sixth Australian crown while his long-time rivals have fallen by the wayside.

World No.1 Rafael Nadal, six-time champion Novak Djokovic and former winner Stan Wawrinka succumbed to injuries, while five-time finalist Andy Murray didn't even get to the starting line.

Yet Federer is again still standing.

Cilic overcame him on the way to winning the 2014 US Open final, but it is his only win in nine encounters and the Swiss defending champion has glided to the brink of another title without dropping a set.

Federer is supremely confident he has it all in place to join Djokovic and Australian Roy Emerson with the most Australian titles.

"It's not about having to improve anything in particular," he said ahead of the final.

"I'm pleased that my game has been good from the very beginning of the tournament so far.

"I mean, I've won all my matches without dropping a set. Things must be all right if I haven't dropped a set and in the final."

Federer was waved through to the final with an all-too-brief semifinal that lasted just 62 minutes when South Korean youngster Chung Hyeon retired with severe foot blisters.

Five of Federer's six matches have finished on or under two hours and he has been on court for a total of 10hr 50min, some 6hr 13mins less than Cilic.

"I would have preferred a normal end (to the Chung match), yes. But I must admit, as well, you do take the faster matches whenever you can," said Federer.

But he knows he faces a tough seasoned opponent in Cilic to win the big one.

"I definitely think him winning the US Open has given him great belief he can do it. If the big moments come about, that he can attain this level," Federer said.

"I like his attitude. He's very professional. He's always very much the same regardless of whether he wins or loses."