Roger Federer into seventh Australian Open final

Roger Federer eased into the final of the Australian Open for the seventh time in his career after South Korean surprise package Hyeon Chung withdrew injured in the second set in Melbourne.

His withdrawal came just days after 2009 winner Rafael Nadal retired in his quarterfinal with Marin Cilic, who Federer is to face in Sunday's final.

Chung, 21, was competing in his first Grand Slam semifinal, having already disposed of Novak Djokovic and both of Germany's Zverev brothers, Alexander and Mischa, en route to the last four.

But, having lost the opening set 6-1 in just 34 minutes, he was forced to undergo treatment on blisters on the sole of his left foot midway through the second set.

Already 4-1 down and having won just 19 of 51 baseline rallies, Chung appeared out of his depth and was struggling with injury. He won one more game to make it 5-2 before informing the umpire of his decision to retire.

"I've played with blisters in the past and it hurts - a lot," said Federer, whose match against Cilic will be a repeat of 2017's Wimbledon final, that the Swiss won in straight sets.

"You can make things worse by carrying on so sometimes it's best to stop. It's bittersweet. I'm happy to be in the final, but not like this. He [Chung] has played such a wonderful tournament and shown what he can do. He'll be a top-10 player in years to come."

Wimbledon final rematch

Looking ahead to Sunday's meeting with Cilic, who beat Great Britain's Kyle Edmund in the other semifinal, Federer revealed that the two had actually trained together on holiday, and said he hoped that this final would be more of a contest than their Wimbledon meeting.

"Marin had injury problems [at Wimbledon] too but I know he's in good shape this time around," he said. "I'm excited to face him, we know each other well, in fact we even played together in the Maldives! Perhaps training in tropical conditions has helped us both to reach the final here!"