Melbourne - It's back to the drawing board for ailing 12-time Grand Slam champion Novak Djokovic with his immediate playing future uncertain after an injury-ravaged exit from the Australian Open.
The former world No 1 cut a disconsolate figure as he played to the bitter end in a agonising defeat to South Korean young gun Chung Hyeon in Monday's fourth round, ending his chance, for now, of a seventh Australian title.
The 30-year-old Serb leaves Australia to reassess his options after a persistent right serving elbow injury flared along with a hip injury.
Djokovic was playing his first tournament in six months after opting against elbow surgery to ease his way back to the game.
But it all spectacularly unravelled on Rod Laver Arena as he winced in pain through his physical ordeal as Chung claimed his greatest win.
The question now for Djokovic is whether this setback is temporary or more signs of a painful, irreversible decline.
"It's frustrating, of course, when you have that much time and you don't heal properly. But it is what it is," he said in the wake of his defeat.
"There is some kind of a reason behind all of this. I'm just trying my best obviously because I love this sport.
"I enjoy training. I enjoy getting myself better, hoping that I can get better, perform and compete.
"This was one of those days where, unfortunately, it was too much to deal with."
Djokovic, who spent four years at No.1 in the rankings, has slipped to 14 and may edge to 13 in the new rankings after the Open, but he could face some time out to fully recover from his troublesome elbow.
"It's not great. At the end of the first set it (elbow) started hurting more. So, yeah, I had to deal with it till the end of the match," he said.
"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."
Djokovic has been forced to tinker with his serve to compensate for the elbow, with a noticeable diminishing of his power.
A flesh-coloured compression sleeve he wore on the right arm during the tournament also appeared to have little effect.
"I felt the level of pain was not that high that I needed to stop the match, even though it was compromising my serve," he said after his defeat.
Djokovic hasn't won a Grand Slam since the 2016 French Open and it appears his grinding style of play has taken its physical toll.
Stan Wawrinka is another ailing great whose future is uncertain after he slumped out in the second round in his first tournament since Wimbledon following left knee surgery.
Andy Murray pulled out of the opening Grand Slam of the year before it started and has since undergone hip surgery with no sign yet when he will return.