WATCH: Disbelief as player hits winner from other side of net at Australian Open

Pablo Carreno Busta pulled off one of the most audacious winners the Australian Open has ever seen as he retrieved the ball from his opponent’s side of the net during his second-round match in Melbourne.

Facing Tallon Griekspoor, Carreno Busta found himself scrambling to reach an overhead smash from his Dutch rival which landed on his side of the net but then span backwards.

The Spaniard nimbly charged around the net, squeezing himself past the umpire’s chair before gently stroking the ball into play to win the point.

The shot soon went viral as astounded fans called it “rare and incredible.”

“Is that legal?” pondered one observer, before another clarified: “It is. You can hit in any place without touching net, after the ball hits your space.”

Tennis commentator John Fitzgerald was similarly astounded by the Spaniard’s ingenuity.

“Oh my goodness. Totally legal,” gushed Fitzgerald.

“And great anticipation there from Carreno Busta... playbook right here for this year’s Australian Open.

“This smash comes off the tip of the racket, it spins, just goes over the net and is going back over the other side of the net. Carreno Busta senses it... that’s sensational.

“Completely legal as long as he doesn’t touch the net, and he doesn’t. I’ve never seen that before.”

The remarkable shot helped the Spanish 19th seed on his way to victory in a five-set epic with the unseeded Griekspoor.

Carreno Busta, 30, will next play Sebastian Korda of America in round three in Melbourne as he aims to match – and potentially surpass – his run to the fourth round Down Under in 2018 and 2019.