by After two grueling service games in the third set, Sinner’s physical problems came to the fore and he called on the trainer after saving a break point to take a 3-2 lead.
He received treatment off the field and returned after just over eleven minutes, but it was Rune who hesitated and allowed Sinner to break for a 5-3 lead.
The 13th seed himself needed a medical timeout due to an apparent knee injury before Sinner raced for a love hold to wrap up the set.
There was another 21-minute break in play at the start of the fourth as the pair returned to the dressing room when the net’s anchoring pin came loose in the middle.
The break seemed to benefit Sinner, who battled their way into a 5-2 lead and served out the win after three hours and thirteen minutes.
“It was really tough. I knew in my mind he had some really long games, so I tried to stay there mentally,” Sinner added.
“Today the support meant so much to me, I really needed you today. It’s 90% of you and 10% of me trying to make you happy.”
Sinner is on a 17-match winning streak, with his last defeat coming in the Beijing Open final against Carlos Alcaraz in October.
There is potential for an all-Italian semi-final draw after Sonego’s victory over 19-year-old Tien in four sets.
Tien was pushing to become the youngest man to reach the last eight in Melbourne since 17-year-old Goran Ivanisevic in 1989, but struggled with a right thigh injury from being tied up.
“Today was so tough, I’m so sad he had a problem. It’s not the right way to win, but I’m so happy I reached the quarter-finals,” said 29-year-old Sonego.
