Roger Federer once again overcame long-time rival Tomas Berdych today to set up a semi-final against Next Gen champion Hyeon Chung at the Australian Open.

Defending champion Federer’s 7-6, 6-3, 6-4 win over Berdych extended his winning streak to 14 in Australian Open quarter-finals and to nine in that personal duel. The 19-time major winner leads that head-to-head contest 20-6, including all five meetings at Melbourne Park.

The 36-year-old Swiss star overcame a shaky start, dropping his opening service game and uncharacteristically challenging the chair umpire because of a technological fault.

“I had to get a bit lucky. A bit angry. A bit frustrated maybe at the umpire,” Federer said. “Anyway, glad to get out of that first set. It was key to the match.

“That first set could have gone either way. He deserved it, actually. I stole that one a little bit.”

Chung became the first Korean to make a grand slam tennis semi-final when he beat No 97-ranked Tennys Sandgren 6-4 7-6 (7/5) 6-3 in the afternoon match on Rod Laver Arena.

The 21-year-old Chung hadn’t let up when upsetting No 4 Alexander Zverev or six-time Australian Open champion Novak Djokovic en route to the quarter-finals, but he let his guard down in the last game and needed six match points and to fend off two break points to hold off Sandgren.

“In last game, I think at 40-love … if I win one more point, I make history in Korea. I have to think about the ceremony, something,” he said, explaining how he got slightly ahead of himself. “After deuce, break point, I was like, no, nothing to do with ceremony. But just keep playing — keep focused.”