Defending Australian Open champion Jannik Sinner advanced to the quarterfinals after a 6-3, 3-6, 6-3, 6-2 victory over No. 13 seed Holger Rune.

The match, which featured a stunning 37-shot rally, was marked by multiple interruptions, including a lengthy medical timeout and a net malfunction.

Sinner, who had been battling illness ahead of the match, acknowledged that he struggled with fitness early on, revealing he did not warm up before the match.

“Today was a very strange morning. I didn’t even warm up today, trying to go on court as fit as I could. I knew in my mind right before the match that I would struggle today,” said Sinner, who noted he was mentally prepared for a tough match.

The match saw Sinner take a medical timeout after a doctor and physio visited him in the third set.

Rune, who received treatment on his knee during a break, had to wait for over 11 minutes before resuming play.

Further delays occurred when a fault in the net caused a stoppage of nearly 20 minutes in the fourth set.

Despite the interruptions, Sinner remained focused and sealed his win with a dominant performance.

“I served very well. Quality shots then gave me confidence to fight on,” Sinner said.

“The time off the court, me and the doctor talked a little bit. It helped me today and also shows this tournament has great organization. They really take care of the players.”

Sinner, who has now won 18 consecutive hard-court major matches, will face either Alex de Minaur or Alex Michelsen for a spot in the semifinals.