South Korean sensation Hyeon Chung is through to his maiden grand slam semi-final after scoring a straight-sets victory over American surprise packet Tennys Sandgren 6-4, 7-6 (7-5), 6-3 in their unexpected Australian Open quarter-final at Rod Laver Arena on Wednesday.

Chung, the first Korean tennis player to make it to the final four of a major, will now face either Roger Federer or Tomas Berdych for a spot in Sunday night's final.

"Whoever win, I'm playing. I don't care," a jubilant Chung said.

Backing up from his stylish straight-sets victory over six-time winner Novak Djokovic, Chung showed no signs of a psychological letdown as he broke Sandgren four times on Rod Laver Arena to storm into the last four in two hours and 28 minutes.