‘Distressed’ world No.1 Jannik Sinner struggles in stifling heat during Australian Open fourth-round match

World No.1 Jannik Sinner has struggled in the stifling Melbourne heat before overcoming adversity in his fourth-round match at the Australian Open.

The defending champion defeated Holger Rune 6-3, 3-6, 6-3, 6-2 in just over three hours, but there were some scary scenes in the middle of the match.

Sinner served a double fault to gift Holger Rune the opportunity to serve out the second set, with the 13th seed duly levelling the match at one frame apiece.

But what was described as “worrying signs” emerged during the break between sets. Sinner was pictured clearly affected as he sat on his bench.

“He looks distressed. He doesn’t take water, there is no towel. He looks ill,” Todd Woodbridge said on Nine.

Jim Courier noted the Italian was “heaving for air” in the 33C conditions.

“He looked like his stomach didn’t feel right. He is definitely suffering big time in this heat and that is a surprise to me. I did not see this coming,” he said.

Sinner eventually stood to leave the court but was seemingly unaware of the direction he needed to walk.

“He looks disoriented, didn’t even know where he was heading,” Courier said.

“He almost looks like a zombie walking across the court.”

Sinner soon returned but even then Courier realised the top seed had failed to give himself the maximum opportunity to recover.

“What is interesting is he didn’t take a shirt to go change,” the tennis great said.

“He could have bought himself two more minutes of rest time if he had changed his shirt or shoes, because you get an extra couple of minutes if you do that. So he is not thinking clearly either, because he should have done that.”

Sinner held to love to open the third set but concerns lingered as he appeared to lose his balance in the third game.

Long rallies — including one described as the point of the tournament — later in the same game conspired to make things more difficult for the title contender as he leaned on his racquet to stay on his feet.

Sinner was spotted shaking during the next changeover.

Courier recalled Sinner vomiting on court at a tournament in Beijing in October 2023 before going on to win the match and the tournament.

“He has shown a history of being able to play through some physical duress, but that was in cool conditions and best-of-three sets,” he said.

“That is very different to what we are facing here.”

After the break between sets, Sinner continued to struggle but managed to keep things on serve, including a marathon effort to save break point with arguably the point of the tournament.

At 3-2, he called for a medical time out and appeared to have his blood pressure tested.

He then left the court for further treatment.

“It seems more than just the heat,” Courier added. “You’re not going off the court if it’s a loss of conditioning issue.”

After an 11-minute break in play, Sinner returned to the court and continued to play.

He immediately looked better and able to land the crucial break in the eighth game.

The injury drama continued with Rune calling for the trainer before Sinner served out the set.

There was another delay during the fourth set when the net broke and both players went inside.

Sinner returned the better and dominated the final set to run out victorious.

“It was very, very tough,” said Sinner in his on-court interivew.

“I knew in my mind that (Rune) also had some very long matches before this one, so I tried to stay in there mentally.

“I just tried to stay connected with my service game and then in the return games, it was trying to see what happens.

“Today the support meant so much to me, so thank you so much.

“I really needed you guys today - so it was 90 per cent yours and 10 per cent me trying to make you happy.”