Hyeon Chung defended his decision to retire in the second set of the Australian Open semi-final against Roger Federer after succumbing to the pain of a badly blistered "red raw" foot.
Chung came from nowhere to reach the last four at Melbourne Park, claiming the scalp of Novak Djokovic before being dominated by defending champion Federer - who will play Marin Cilic in Sunday's final.
Nineteen-time grand slam champion Federer took just over half an hour to win the first set 6-1 and led 5-2 in the second when the unseeded Chung decided he could not continue.
The South Korean called for a medical timeout to get his foot taped, but ended his dream run soon after.
Unfortunate scenes on @RodLaverArena with Hyeon #Chung forced to retire early in his Men's Singles SF against @RogerFederer-- #AusOpen (@AustralianOpen) January 26, 2018
Federer is through to his 7th final here at Melbourne Park. #AusOpenpic.twitter.com/bjsGymyXB6
"It really hurt, I could not walk anymore," said the 21-year-old. "I think I did right thing.
"I'm happy to be able to make the semis in a grand slam. I want to be stronger next year."
Chung's agent, Stuart Duguid, explained the extent of the damage suffered by the Next Gen ATP Finals champion.
"It's like worse than regular blisters. Over the last few days, it was blister under blister under blister. He had it shaved off. Now it's red raw," said Duguid.
"They tried injections to see if it numbed the pain. It didn't work."
He added: "I think a lot of players get callouses. As they go along, they shave them down. Because he has played so many matches in the row, I think that's why it was a build-up. I think that's how they started."