Roger Federer says he has nothing to improve in his stellar game as he closes in on a 20th Grand Slam title at the Australian Open .

The Swiss great had an unimpeded march into Sunday's final against Marin Cilic with an abrupt-ending semi-final against South Korean young gun Chung Hyeon on Friday.

The defending champion was leading 6-1, 5-2 when Chung called it quits with foot blisters after being treated in a medical timeout for the problem just two games earlier.

Federer hasn't dropped a set in his six matches and is zeroing in on his seventh Australian title in his 30th Grand Slam final. 

“I just have to play a good match. At this point it's not about having to improve anything in particular,” he told reporters. “I think I've done everything pretty well. I just hope I'm going to have a good start to the match. I hope I can mix up my game.

“I hope I can start serving well from the get-go, not get into too much trouble early. I hope I can read his serve and all these things.”

Ominously, Federer added: “I'm just pleased that actually 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'm in this stage right now not having dropped a set and in the final.”

Federer beat French 29th seed Richard Gasquet and Czech 19th seed Tomas Berdych to get to his eagerly awaited semi-final with Novak Djokovic-conqueror Chung, but the contest proved a non-event. He broke Chung's serve four times off 11 break points and only had one break point on his own service.

The Swiss second seed hit 24 winners while Chung made 17 unforced errors in 14 games, eight of them off his normally potent forehand which Federer targeted.

“I knew Chung was having issues with his feet going into it. But I knew he also had issues going into the match against Novak. He handled that very well. The same against Tennys Sandgren,” he said.

“For me, I was trying to block that away and just play Chung himself. “If he had no issues, well, that's normal. If he has issues, well, bad luck for him, and I'll take advantage of it.”

Federer has an imposing win-loss record of 93-13 at the Australian Open and overall his Grand Slam record stands at 331-52.