Novak Djokovic beat 26th seed Tomas Machac in straight sets and will next face Jiri Lehecka. Coco Gauff thumped Leylah Fernandez to book pre-quarters berth.

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.

Naomi Osaka, a two-time champion in Australia, stopped playing because of a strained abdominal muscle after dropping the first set of her match against Tokyo Olympics gold medalist Belinda Bencic.