The day's other big story once again centred on Tennys Sandgren, who followed up his upset of Stan Wawrinka in Melbourne with a five-set victory over fifth seed Dominic Thiem, winning 6-2, 4-6, 7-6 (4), 6-7 (7), 6-3.
Roger Federer and Simona Halep were also in action, as the former enjoyed a straight-sets victory against Marton Fucsovics, winning 6-4, 7-6 (3), 6-2, and the latter dismissed Naomi Osaka 6-3, 6-2.
TV Info: Eurosport 1 (UK) and ESPN2 (U.S.)
Sunday Replay: Eurosport 1 from 1:30 p.m. (GMT); Tennis Channel from 12 p.m. (ET)
Full Results and Schedule: AusOpen.com
Djokovic Suffers 4th-Round Exit
An electric start from Chung saw him capitalise on a sluggish opening from Djokovic, per Eurosport UK:
The Serb's resilience saw him battle back from 4-0 down in the opener to force a tiebreaker, but the South Korean impressively held his nerve to draw first blood.
Former tennis star Annabel Croft gave her take on the superb contest that was unravelling:
Chung enjoyed a similarly strong start to the second set as he raced to a 3-0 lead, with Djokovic's elbow injury hampering his ability to resist, per two-time Australian Open finalist Pat Cash:
While Djokovic may not have been at his peak, Chung undoubtedly was, and it was only because of that he was able to take advantage of the 14th seed's predicament.
A late break allowed Chung to take the second set, and the pair shared two breaks apiece in a breathless third set.
The set went to a tiebreaker, with Chung saving some of his best tennis for it:
The Korean eventually held on for a deserved win, successfully closing out the tiebreaker to three.
Sandgren had never won a Grand Slam match prior to this year, but he now has four under his belt and collected some big scalps along the way.
Thiem did not make it easy for the world No. 97, hitting back each time the American took the lead to ensure the match went the distance.
It came down to a clinical difference in the decider—both players earned one break point, but where Sandgren took his, Thiem failed to.
Sports journalist Ashish Magotra noted how far Sandgren has come:
In the day's other results, Madison Keys breezed past Carolina Garcia 6-3, 6-2, Angelique Kerber mounted an impressive comeback to beat a spirited Su-Wei Hsieh 4-6, 7-5, 6-2 and Tomas Berdych beat Fabio Fognini 6-1, 6-4, 6-4.