Novak Djokovic admitted he got lucky after opponent Lorenzo Musetti retired hurt on Wednesday to send the Serbian great into a semifinal against either two-time reigning champion Jannik Sinner or Ben Shelton.
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Earlier on day 11 in Melbourne, Jessica Pegula and Elena Rybakina both won in straight sets and will meet for a place in the final.
The 38-year-old Djokovic, chasing an all-time record 25th Grand Slam crown, has the tennis gods smiling on him.
His last-16 opponent Jakub Mensik pulled out without a ball being hit and now Musetti was forced to retire with the Italian leading 6-4, 6-3, 1-3 on Rod Laver Arena.
The fifth-seeded Musetti was well on top when he needed treatment on his upper right leg, and with his movement badly impeded, was forced to throw in the towel.
"I feel really sorry for him, he was the far better player, I was on my way home tonight," said Djokovic, who had been uncharacteristically error strewn and was staring down the barrel.
"It has happened to me a few times. He was in full control.
"So unfortunate, I don't know what else to say.
"He should have been the winner today, no doubt. I am extremely lucky to get through this one today."
Djokovic has been trying to move past Margaret Court and clinch the landmark 25 since his last major title at the US Open in 2023.
It has proved increasingly difficult with the emergence of Sinner and world No 1 Carlos Alcaraz.
Djokovic, who needed treatment during the match for a blister, added: "I am going to double my prayers and gratitude tonight to God for giving me this opportunity again."
Italian second seed Sinner and United States eighth seed Shelton face off in the last match of the day, with Djokovic awaiting in the semifinals.
PEGULA SETS UP RYBAKINA CLASH
Moscow-born Kazakhstani Rybakina, the 2022 Wimbledon champion, stunned second seed Iga Swiatek 7-5, 6-1 to book her spot in the last four.
Pegula swept aside Amanda Anisimova 6-2, 7-6 (7/1) in an all-American affair.
Rybakina has made the Melbourne final once before, in 2023, when she lost in three tough sets to Aryna Sabalenka.
The 26-year-old fifth seed took her latest victory in her stride, saying a calmer mindset helped in the heat of battle.
"In the beginning, when it's the first final and you go so far in a tournament, of course you are more emotional," said Rybakina.
"Now I feel like I'm just doing my job, trying to improve each day. So it's kind of another day, another match."
Defeat denied Swiatek in her latest bid for a career Grand Slam of all four majors, having already won Wimbledon, the French Open and the US Open.
Sixth seed Pegula and Rybakina have shared three wins each in their six matches so far.
Pegula is yet to drop a set this year in Melbourne and is arrowing in on her first major crown at the age of 31.
"It's awesome," Pegula said of reaching her first Australian semifinal, having beaten defending champion Madison Keys in the previous round.
She was helped by an error-riddled display from fourth seed Anisimova, who racked up 44 unforced errors to Pegula's 21.
Her frustrations boiled over at the end as her hopes of reaching a third major title in a row melted away in a blur of mistakes.
Two-time champion Sabalenka faces Ukrainian 12th seed Elina Svitolina in the other semifinal.