Melbourne, Jan 20 (IANS): Defending champion Jannik Sinner had to dig deep into his physical and mental reserves at Australian Open 2025 on Monday to keep his title defense on track as the Italian saw off Holger Rune of Denmark 6-3, 3-6, 6-3, 6-2 to advance to the quarterfinals.

In hot and humid conditions, the top-seed Italian was struggling midway through his fourth-round match with Rune. But after medical timeouts and even a lengthy break for a broken net, he found a way to win.

Sinner, who won his first Grand Slam title here last year, took the first set in 33 minutes to set up a quarterfinal against either Australia’s big hope Alex de Minaur or young American Alex Michelsen.

Sinner was wrapping an ice towel around his neck like a scarf at every change of ends, but he still looked in control in the early stages of the second set. Aided by Rune’s 16 unforced errors, Sinner clinched the third set and then broke early in the fourth to reach the quarterfinals at Melbourne Park for the third time, the tournament reports.

“I knew in my mind that he also had some very long matches, so I tried to stay there mentally. I tried to stay connected with my service game and then in return games see what happened," said Sinner.

Struggling in 32-degree heat, Sinner called a medical timeout – during which the tournament doctor took his pulse - after two gruelling service games midway through the third set.

Sinner hinted that he had begun the match feeling less than 100 per cent. "This morning was a very strange morning because I didn’t even warm up, I was trying to go on court as fit as I could. I knew in my mind before the match that I would struggle. Game-wise I played well today, I served well. The time off the court, me and the doctor, we talked a little bit, it helped me today," he said.