Blistered feet forced Hyeon Chung to retire when trailing Roger Federer 6-1, 5-2 in their Australian Open semi-final on Friday.

Chung had treatment on a blistered foot midway through the second set and he tried to play through the pain but eventually threw in the towel after 63 minutes of play.

‘I could tell something was wrong before he took the timeout,’ said Federer. ‘But he has a great composure and I think we’re going to see a lot more from him. Top 10 for sure.

‘The rest, I don’t know, I don’t want to put too much pressure on him. I think he’s going to be a great player.’

Federer progresses to his 30th Grand Slam final, where victory against Marin Cilic would clinch his 20th Grand Slam title.