Chung Hyeon celebrates after beating Alexander Zverev at the Australian Open on Saturday. Photo: Vincent Thian/AP

MELBOURNE – Chung Hyeon became the first South Korean man ever to reach the round of 16 at the Australian Open with a five-set upset win over fourth seed Alexander Zverev on Saturday.

The 58th-ranked Chung beat a top-five-ranked opponent for the first time with his 5-7 7-6(3) 2-6 6-3 6-0 victory in three hours and 22 minutes on Rod Laver Arena.

He will face either six-time champion Novak Djokovic or Spaniard Albert Ramos-Vinolas in Monday’s fourth round.

Chung’s feat also makes him only the third South Korean player – man or woman – to reach the round of 16 at a Grand Slam.

“It was really tough, he is a really good player and we know how to play each other,” said the glasses-wearing 21-year-old, who trained in the heat of Thailand before coming to Melbourne.

“I played Novak two or three years ago, so if he wins tonight, I just want to enjoy things on the court.”

It was another disappointing exit from a Grand Slam for the highly-ranked Zverev, whose game fell apart in the final set and was issued with a warning for smashing his racquet in frustration after a service break.

While he won five titles and was one of just four players to beat Roger Federer last year, he has yet to get beyond the fourth round at a Grand Slam.

To rub salt in the wounds, it was a Zverev family double for Chung, who eliminated older brother Mischa in the first round of the tournament.

Zverev got off to a quick start to hold three set points with a backhand cross court and took the opening set in 44 minutes when Chung netted a forehand.

But Chung, who defeated Russian Andrey Rublev to claim his first title at the Next Gen ATP finals in Milan last year, levelled the set scores with a tiebreaker win after holding three set points when the German netted a forehand.

Zverev hit the front with a break in the third game on the way to taking the third set, but Chung would not go away.

The South Korean took the match into a fifth set with a booming ace and Zverev handed over a break in the opening game of the deciding set with a double fault on triple break point.

Zverev was given a racquet abuse warning by the chair umpire after slamming his racquet into the court in frustration and suffering a second service break to trail 3-0 as his game fell away.