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.

While there have been plenty of surprises in the men’s bracket so far, most of the top women have progressed through the draw without an issue.

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.