MELBOURNE (AFP) - Chung Hyeon became the first South Korean man to reach the round of 16 at the Australian Open with a five-set upset win over fourth seed Alexander Zverev on Saturday (Jan 20).
The 58th-ranked Chung beat a top-five ranked opponent for the first time with his 5-7, 7-6 (7-3), 2-6, 6-3, 6-0 victory in 3hr 22min 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 bespectacled 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-rated Zverev, whose game fell apart in the final set and was issued with a warning for smashing his racket in frustration after a service break.
While he won five ATP Tour 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.
Chung 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 racket abuse warning by the chair umpire after slamming his racquet into the court in frustration as his game fell away.