
Like a smiling assassin, Jannik Sinner has sent a subtle warning to his Australian Open challengers in his first appearance down under since snaring his maiden grand slam crown 12 months ago.
After starting out more saint than sinner, the world No.1 displayed his ruthless streak in a 6-4 7-6 (7-2) exhibition win over Alexei Popyrin on Rod Laver Arena on Tuesday.