Australian tennis player-turned-commentator Rennae Stubbs has made the shock declaration she thinks Jannik Sinner is "guaranteed" to cop a ban when he fronts the Court of Arbitration for Sport (CAS) in April. Sinner won his second Australian Open and third grand slam title last week, but his immediate future in the sport is under a cloud.

Facing Sinner reminded Alexander Zverev of trying to solve the challenge presented by the 24-time major champion Djokovic.