First came the medical timeouts, one each for Jannik Sinner and Holger Rune with the temperature above 90 degrees Fahrenheit (32 Celsius) at the Australian Open. Then came the unusual sight of a 20-minute delay because the net at Rod Laver Arena detached from the court after being hit by a big Sinner serve.

The defending champion moved into the quarterfinals at Melbourne Park on Monday by eliminating the 13th-seeded Rune 6-3, 3-6, 6-3, 6-2.

The World No. 1, despite feeling unwell in sweltering conditions, kept up his title defense with a four-set triumph.

Holger Rune didn't have anything against Jannik Sinner taking a medical timeout but noted that a lengthy break ruined his rhythm. After the world No. 1 started to physically struggle late in the second set of their Australian Open round-of-16 match - the Italian's hands were shaking and his movement was impacted - the Dane won that set and also had the upper hand early in the third set.

Jannik Sinner has revealed that he felt unwell ahead of his win over Holger Rune at the Australian Open, and is relieved to be through to the quarter-finals.

Jannik Sinner came through a gruelling match against Holger Rune at the Australian Open, but there were concerns over his health during the clash as he admitted he was not feeling well before the encounter even got underway.

Jannik Sinner is through to his third Australian Open quarter-final within four years. The Italian faced Holger Rune in the fourth round at Rod Laver Arena and earned a 6-3, 3-6, 6-3, 6-2 victory in three hours and 13 minutes.