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.

Two-time Australian Open champion Naomi Osaka has stopped playing because of an injury after dropping the opening set of her third-round match against Belinda Bencic.

Naomi Osaka ’s return to Grand Slam competition ended prematurely on Friday, as the two-time Australian Open champion was forced to retire from her third-round match against Belinda Bencic due to a strained abdominal muscle. Osaka had dropped the opening set in a tiebreaker, 7-6 (3), before informing the chair umpire she could no longer continue.