Melbourne: Six-time champion Novak Djokovic is out of the Australian Open, beaten 7-6 (4), 7-5, 7-6 (3) in the fourth round by Hyeon Chung, a 21-year-old South Korean ranked 58th.
The point of the match came in the third-set tiebreaker when Chung hit a cross-court passing shot to put him within two points of victory. It ended minutes later when Djokovic hit a backhand wide.
Djokovic, who trailed the first set 4-1 but fought back to 5-5 before losing the tiebreaker, took a medical timeout to have his right arm massaged before the start of the second set.
He spent six months off the tour last year with a right elbow injury and said he waited until just before the tournament began to decide if he was fit enough to play.
Chung will now play another relatively unknown player in the quarterfinals - Tennys Sandgren, a 97th-ranked American who beat No. 5-seeded Dominic Thiem earlier Monday.
Here's the Men's quarter-final draw for the Australian Open 2018 after Monday's matches:
Rafael Nadal (ESP x1) v Marin Cilic (CRO x6)
Grigor Dimitrov (BUL x3) v Kyle Edmund (GBR)
Roger Federer (SUI x2) v Tomas Berdych (CZE x19)
Tennys Sandgren (USA) v Chung Hyeon (KOR)