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.

Novak Djokovic moved into the fourth round with his most confident performance of the week,against the 26th-seeded Tomas Machac.

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,