An ailing Novak Djokovic crashed out of the Australian Open in the fourth round as up and comer Hyeon Chung clinically took advantage of the six-time champion's elbow injury to win 7-6 (7-4) 7-5 7-6 (7-3).

The Serbian, who had also struggled with his hip in the third round, was on the back foot from the off and failed to claw back the first set before suffering further at the start of the second.

Djokovic's fighting spirit never wavered, but he could not shake off NextGen champion Chung, who was unrelenting en route to claiming the biggest scalp of his career.

Chung – the first Korean male or female to reach a grand slam quarter-final – had said prior to the match that he would "just be happy to share the court with Novak", but he was far from starstruck and an outstanding performance made him a deserved winner - albeit Djokovic, who missed six months before returning to play in Melbourne, was undoubtedly hindered by his injury. 

The 21-year-old will now face another shock quarter-finalist in Tennys Sandgren on Wednesday.