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

MELBOURNE, Australia — The screw holding the net in place at the Australian Open’s main stadium got jarred loose during defending champion Jannik Sinner’s fourth-round victory against Holger Rune, delaying play for about 20 minutes early in the fourth set.

Defending champion Jannik Sinner’s consecutive-sets streak has ended in the second round of the Australian Open.

Lorenzo Sonego will take on American Ben Shelton in the other men’s quarter-final on Jan 22. Read more at straitstimes.com.

In the quarterfinals, Sinner will face No. 8 Alex de Minaur of Australia, who ousted American Alex Michelsen 6-0, 7-6 (5), 6-3. It will be the first quarterfinals appearance for de Minaur in his home country's Grand Slam, and he became just the third Aussie man to reach the round in 20 years.

Shelton is the 25th American man in the Open Era man to reach the semis in Melbourne. He’s bidding to become the second straight American man to reach a Slam final after Taylor Fritz lost to Sinner in the U.S. Open final, and the first since Andy Roddick at the 2003 U.S. Open to win a major.

Defending champion Jannik Sinner has moved into the quarterfinals at the Australian Open after beating Holger Rune during a match slowed down by medical timeouts for each player and a delay because the net got knocked loose.

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.

Here's why each semifinalist can go on and lift the trophy:

The 23-year-old Pole moved closer to a first Australian Open title but she will first face 19th seed Madison Keys in the semifinals. The former US Open finalist overcame a slow start to edge 28th seed Elina Svitolina 3-6, 6-3, 6-4 in one hour and 53 minutes.

Tennis legend Boris Becker has backed up criticism levelled by Ben Shelton against some of the interviews being conducted after matches at the Australian Open. Shelton launched an extraordinary broadside at Australian Open and Channel 9 officials during his press conference after beating Lorenzo Sonego on Wednesday to make the semi-finals.