Defending champion Jannik Sinner scorched American eighth seed Ben Shelton 6-3 6-4 6-4 and moved into the Australian Open semi-finals, setting up a blockbuster showdown with 10-times winner Novak Djokovic.

The second seed, who is firmly on course for his third title at Melbourne Park in as many years, tightened his vice-like grip on the rivalry with Shelton by sealing his ninth straight win, all of which have been without conceding a set.

Sinner looked to be on his way when he pulled off a stunning winner by gently caressing the ball around the net post en route to breaking in the fourth game, before claiming the opening set with little trouble.

Shelton went up a gear and earned a breakpoint at 1-2 down in the second set, but Sinner snuffed out the challenge to surge into another commanding lead despite looking off-colour at times and he closed out the frame when the American sent a shot long.

A couple of breakpoints came and went in the fifth game of the third set but Sinner benefited from a Shelton double fault to go 5-4 up and wrapped up the win on serve to ensure his meeting with 24-times major champion Djokovic.

-Shrivathsa Sridhar/Reuters