Novak Djokovic
Novak Djokovic struggled with an elbow injury throughout his shock fourth-round defeat to Chung Hyeon SAEED KHAN/AFP/Getty Images

Novak Djokovic says the current condition of his elbow is "not great" and admits he is unsure if he will need to spend more time on the sidelines after the 12-time Grand Slam winner was ousted in the fourth round of the Australian Open on Monday (22 January) thanks to a shock straight-sets defeat to world number 58 Hyeon Chung in Melbourne.

Djokovic returned to competitive action for the first time since the 2017 Wimbledon Championships last week after a lingering elbow issue that had been bothering him for the previous 18 months, beating Donald Young, Gael Monfils and Albert Ramos-Vinolas before falling to Chung in a major upset.

The 30-year-old, seeking a record seventh Australian Open title, was clearly struggling with the problem early on and received treatment on his sleeved right elbow after dropping the first set on a tiebreak despite fighting his way out of a 4-0 hole.

It appeared at one stage as if Djokovic, also struggling with a hip complaint, would be forced to retire, but he persevered and battled hard to try to overturn similar deficits in the second and third sets before eventually succumbing to a 7-6 (7-4) 7-5 7-6 (7-3) loss to Chung, who became the first South Korean player ever to reach the quarter-finals of a Grand Slam.

"Yeah, it's not great," Djokovic said of his health in a post-match press conference. "Unfortunately, it's not great. Kind of end of the first set it started hurting more. So, yeah, I had to deal with it till the end of the match."

Djokovic did not want to focus on his injury struggles and deny Chung the limelight after that victory over his idol, but admitted his frustration that the elbow had not properly healed despite a six-month absence. He said the level of pain was not so high that he felt he needed to stop the match, although it was clearly compromising his serve.

Asked if he could now need to take more time away from the court, he responded: " I really don't know. Now I don't know. I have to reassess everything with my team, medical team, coaches and everybody, scan it, see what the situation is like. Last couple weeks I played a lot of tennis. Let's see what's happening inside."

Day eight round-up

Chung will face Tennys Sandgren in the last eight after the American world number 97 and Australian Open debutant stunned fifth seed Dominic Thiem in five sets in another huge upset.

Defending men's champion Roger Federer is still yet to drop a set at this year's tournament after easing past Hungarian Marton Fucsovics 6-4 7-6 (7-3) 6-2 and will meet Tomas Berdych for a place in the semi-finals - where he would play Chung or Sandgren - after the Czech right-hander defeated Fabio Fognini in straight sets.

In the women's draw, world number one Simona Halep eased past Naomi Osaka 6-3 6-2 and Angelique Kerber battled back from a one-set deficit to overcome Hsieh Su-wei. The 2016 champion now takes on Madison Keys, who proved far too strong for eighth seed Caroline Garcia.