An unstoppable Roger Federer has advanced to his seventh Australian Open final, with unseeded South Korean opponent Hyeon Chung retiring hurt during their semi-final.
Federer had conceded just three games on Friday night when Chung, who struggled with a blister on his left foot, shook the umpire's hand with the Swiss maestro ahead 6-1 5-2.
The 19-time grand slam winner will face Croatia's Marin Cilic in Sunday night's title decider.
Down 4-1 in the second set, Chung called for the trainer and had a heavily bandaged left foot examined and re-strapped.
The 21-year-old threw in the towel a short time later.
It was a brutal ending to a brilliant campaign in which Chung conquered six-time champion Novak Djokovic and fourth seed Alexander Zverev on the way to the final four.
"I've played with blisters in the past, and it hurts a lot," Federer said.
"At some point, it is just too much and you can't take it anymore, when you realise there is no way you can come back and you make things really worse - it is better to stop.
"That's why this feels bittersweet. Obviously, I'm incredibly happy to be in the finals but not like this, and he has played a wonderful tournament, so credit for him for trying so hard today again."
Federer looked in incredible touch ahead of facing Cilic in a rematch of last year'S title victory at Wimbledon.
The 36-year-old smashed 24 winners compared to Chung's nine and won a staggering 94 per cent of points off his first serve.
Perhaps the only moment that went against Federer was during the second set when the chair umpire ruled he had not been hindered by a linesman's correction call.
"You're kidding me," an incredulous Federer said.
"It's a bulls*** argument. It was during the shot."
Federer has overtaken Djokovic for the most Australian men's finals reached in the Open era.
He will match Djokovic's record for most Open era title victories at Melbourne Park if he can defeat Cilic in their 10th career meeting.
