Novak Djokovic throws his ailing 37-year-old body into an Australian Open semi-final against Alexander Zverev on Friday while defending champion Jannik Sinner faces Ben Shelton.
Djokovic and German world number two Zverev are first up at 2:30 pm (0330 GMT) on Rod Laver Arena as the Serbian great closes in on a record 25th Grand Slam title.
Djokovic rolled back the years to defeat Carlos Alcaraz, aged 21, in four sets in the quarter-finals in Melbourne.
But his upper left leg was taped after a medical timeout and he needed painkillers to battle through.
“I’m concerned. I am, to be honest, physically,” said Djokovic, a 10-time champion at Melbourne Park.
“But if I manage somehow to be physically good enough, I think mentally, emotionally I’m as motivated as I can be.”
Djokovic will have benefitted from two full days of recovery, having played on Tuesday, and few will be betting against him despite his creaking limbs.
The 27-year-old Zverev is into the semi-finals for a second straight year and is laser focused on finally winning a Grand Slam after a decade of trying.
Last year at the same stage he crashed to Daniil Medvedev in five sets after holding a 2-0 lead and is understandably wary of Djokovic, even if he is carrying an injury.
“I’m going to prepare myself for a very intense and high-level match,” he said.
Djokovic and Zverev have met 12 times previously, with the Serb winning eight of them, including in the quarter-finals in Melbourne in 2021.
They last faced off in 2023 in Cincinnati, with Djokovic again the winner, in two close sets.
Italian world number one Sinner goes into his clash as hot favourite after a commanding straight-sets win over Alex de Minaur in the quarter-finals.
But he will have to tame the booming serve of 21st seed Shelton.
“One of the biggest serves we have on tour. He’s a very aggressive player, an all-around player. He can go to the net. He can stay back,” Sinner said of the American, who is in his second semi-final at a major.
He reached the last four at the US Open in 2023.
“It’s a difficult match for both of us,” added Sinner.
“We know each other a little bit better now. We had some tough matches in the last year, so let’s see what’s coming.”
Sinner has won four of their five matches so far, underlining the scale of the task facing Shelton, who at 22 is a year younger.
“I’m really looking forward to it,” said Shelton.
“I think that anytime you get to line up against the best in the world is a great opportunity to improve your game and see where you’re at, and that’s what Friday will be for me.”
