MELBOURNE, Australia — Hyeon Chung became the first South Korean man to reach the semifinals of a Grand Slam singles tournament, beating Tennys Sandgren, 6-4, 7-6 (5), 6-3, on Wednesday afternoon.

Chung will seek his next milestone against a far more experienced foe: second-seeded Roger Federer, who reached his 14th Australian Open semifinal with a 7-6(1), 6-3, 6-4 win over 19th-seeded Tomas Berdych.

Chung, 21, won a showcase for young ATP talent last November in Milan, and has solidified himself as the leader of his generation with each successive win at this tournament. He beat Mischa Zverev, a quarterfinalist here last year, in the first round; the Sydney International champion Daniil Medvedev in the second round; fourth-seeded Alexander Zverev in the third round; and six-time champion Novak Djokovic in the fourth round.

Chung said his victories had kept him energized.

“When I win the match against top player, never tired,” he said, adding that he was “mentally happy.”