Chung shares photo of the nasty injury that forced him to retire against Federer.

A blistered left foot cut short his semi-final against Roger Federer but Hyeon Chung has won the Swiss maestro’s admiration after a stellar Australian Open campaign.

Federer will face Croatia’s Marin Cilic in Sunday night’s title decider after unseeded South Korean Chung retired hurt while trailing 6-1 5-2 in Friday night’s semi-final.

Down 4-1 in the second set, Chung called for the trainer and had his heavily bandaged foot examined and re-strapped.

The 21-year-old bravely continued playing but was forced to throw in the towel a short time later.

LISTEN: Monique Bowley pleads a case for trigger warning on gruesome sports injuries, on Mamamia Out Loud. Post continues after. 

Chung later revealed he could barely walk after a heavy summer schedule left him with a build-up of blisters.

“Over the last few days, it was blister under blister under blister,” Chung’s agent Stuart Duguid said.

“He had it shaved off. Now it’s red raw.

“They tried injections to see if it numbed the pain. It didn’t work. Much worse than a regular blister.”

. Tonight, I tried very hard to bring my utmost energy to the tennis court as usual. However, I had to make a tough decision given that I cannot compete 100% against Roger, in front of many tennis fans. Please understand. I wish all the best luck for @rogerfederer in the finals. 오늘 저녁 제가 할 수 있는 최선을 다했습니다. 경기를 포기하기 전 많은 생각을 했습니다. 많은 팬분들 앞에서,훌륭한 선수 앞에서 내가 100%을 보여주지 못 하는건 선수로서 예의가 아닌거 같아서 힘든 결정을 내렸습니다. 며칠 뒤에 있을 결승전에 로저 페더러 선수에게 행운이 있기를!

A post shared by Hyeon Chung (@hyeon519) on Jan 26, 2018 at 5:27am PST

It was a brutal ending to a brilliant fortnight in which the world No.58 conquered six-time champion Novak Djokovic and fourth seed Alexander Zverev on the way to the final four.

Federer admitted it was a bittersweet feeling after Chung’s retirement allowed him to advance to his seventh Australian Open final.

But the 19-time grand slam winner had nothing but praise for his opponent, describing him as capable of unseating the older generation that continue to dominate men’s tennis.

“He is already a great player but we are talking about next-level excellence and I think he’s going to achieve that,” Federer said.

“We will see much more of him. Top 10 for sure. The rest, we’ll see – I don’t want to put too much pressure on him.

“He has done very well. I can see why he beat the likes of Novak and Sascha (Zverev) and all the others this week and in the past. I think he is going to be a great, great player.”

Asked what his key goal was for the rest of the year, Chung identified finishing the season without injuries.

The youngster said he had gained plenty of confidence after embarking upon his deepest run at a grand slam.

“I’m happy to be able to make semis in grand slam. I want to be stronger next year,” he said.

“I play really good in last two weeks. I make first round (of) 16, quarters and semis. I play Sascha, Novak, Roger.

“I think I can play better and better in the future.”