Novak Djokovic has overcome some trouble breathing and played quite well for a straight-set victory over 26th-seeded Tomas Machac to reach the fourth round at the Australian Open.

The rise of Jannik Sinner and Carlos Alcaraz vanquished Djokovic's inevitability at the Australian Open, but he is still the main character.

Novak Djokovic, Coco Gauff roll to Australian Open's 4th round. Naomi Osaka retires due to injury and Jessica Pegula was upset in the third round.

MELBOURNE, Australia — Count Novak Djokovic as being in Danielle Collins' corner. He thinks her response to booing fans at the Australian Open was absolutely fine — which should come as no surprise, given the way Djokovic gets into back-and-forths with hecklers at his matches, including Friday night at Rod Laver Arena.