Novak Djokovic was forced to retire from his Australian Open semi-final due to injury after losing the first set against Alexander Zverev on Friday.
Djokovic retired injured after losing the first set 7-6(5) against Zverev to put the German through to his first Australian Open final.
The Serb's upper left leg was again heavily taped after he hurt it in the quarter-finals and he struggled in a grueling opening set before calling time.
It thus ended Djokovic's bid for a record 25th Grand Slam title.
Djokovic left the court to a mixture of boos and applause.
"There is a chance. Who knows," Djokovic said when asked if he may have played at Melbourne Park for a last time.
"I'll just have to see how the season goes. I want to keep going. But whether I'm going to have a revised schedule or not for the next year, I'm not sure.
"I normally like to come to Australia to play. I've had the biggest success in my career here. So if I'm fit, healthy, motivated, I don't see a reason why I wouldn't come," he added.
"But there's always a chance, yeah."
Djokovic, who was aiming for an 11th championship at the Australian Open, hurt his left leg during his quarter-final victory against Carlos Alcaraz.
But there was little indication Djokovic was struggling until late in the set when he noticeably began walking slowly between points and muttering in frustration at his players' box.
After losing the set, he promptly informed Zverev that he could not go on and shook hands with the chair umpire before exiting to a chorus of boos from the crowd.
"The very first thing I want to say is, please guys, don't boo a player when he goes out with injury," Zverev said in his on-court interview.
"I know that everybody paid for tickets and wants to see hopefully a five-set match.
"He has won this tournament with an abdominal tear, won this tournament with a hamstring injury. So please show some respect."
Zverev will meet Jannik Sinner in Sunday's decider.
Defending champion Sinner continued his sizzling Australian Open run with a 7-6(2), 6-2, 6-2 victory over American 21st seed Shelton to reach a second straight final at Melbourne Park.
Sinner's victory made the 23-year-old the youngest man to make multiple finals at the Australian Open since Jim Courier in 1992-93 and kept alive his dream of becoming the first Italian to lift three Grand Slam singles trophies.
Djokovic came into Friday's clash with questions over his fitness after needing medical attention in his four-set quarter-final win.
He said before the match he was worried about his physical condition.
But he has demonstrated remarkable powers of recovery more than once in his career and it didn't appear to hinder him initially.
He moved with his customary zip in an opening service game that featured a 27-shot rally and again in saving four break points as his serve mis-fired.
It was then Zverev's turn to save three break points and keep the match on serve at 2-2, with both players blowing hot and cold.
Another break point went begging for the German at 4-4, with Djokovic barely getting 50 percent of his first serves in.
It went to a tight tiebreak after which Djokovic retired.
Djokovic has now gone five Grand Slams without winning the title he needs to surpass Margaret Court's 24 and become the all-time leader.
He failed to collect one for the first time in seven years in 2024 with his last coming at the 2023 US Open, casting further doubt on whether he will ever get past Court.
The defeat also deprived him of a 100th career title. Roger Federer (102) is the only player, man or woman, to reach the century mark.
"I actually thought I played really well, as well as I played the last 12 months, to be honest," Djokovic said of his tournament run.
"I liked my chances if I was physically fit and ready to battle. I think I was striking the ball very well. A lot of positives to take in terms of how I played.
"I wish Sascha (Zverev) all the best. You know, he deserves his first Slam. I'll be cheering for him."
