Alexander Zverev suffered another grand slam letdown with a five-set defeat by fellow young gun Chung Hyeon in the third round of the Australian Open.

The fourth seed is the highest-ranked player to fall so far in the men’s draw but it was the manner of this loss that will be the most concerning for Zverev and his camp.

The 20-year-old German got into a row with the umpire about the light on Rod Laver Arena and won just five points in the final set to go down 5-7 7-6 (7/3) 2-6 6-3 6-0.

Zverev won five ATP Tour titles last season, including two at Masters level, and climbed to a high of third in the world, yet he has reached the fourth round at a slam only once and has not beaten a top-50 player over a best-of-five sets match.

Zverev has long been seen as the leader of the new generation and chose not to play at November’s inaugural Next Gen Finals because he had qualified for the elite ATP Finals the following week.

In his absence, it was Chung who triumphed and the 21-year-old Korean celebrated reaching the last 16 at a slam for the first time, where he will face either Novak Djokovic or Albert Ramos-Vinolas.

Fifth seed Dominic Thiem had a much easier afternoon after his recovery from two sets down to beat Denis Kudla in round two, seeing off France’s Adrian Mannarino 6-4 6-2 7-5.

The Austrian next meets the aptly named Tennys Sandgren, who had never won a grand slam match before arriving in Australia and won the battle of the unseeded players 5-7 6-3 7-5 7-6 (7/5) against Maximilian Marterer.

Another first timer through to the last 16 is Hungary’s Marton Fucsovics, a former top junior who has struggled to translate that into the senior game. He defeated Nicolas Kicker of Argentina 6-3 6-3 6-2.

Julien Benneteau’s final Australian Open before retirement came to an end with a 3-6 6-2 6-1 4-6 6-3 defeat by 25th seed Fabio Fognini.