The two best men's players in the world are reconfiguring the sport before their opponents' eyes. They don't know what to do about it

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.

Carlos Alcaraz was in fine form as he cruised to a first-round win at the Australian Open, but it was his comments on Jannik Sinner which drew attention.