Nathaniel Drummond, 19, was taking part in the race on Sunday at Seacliff Beach in Adelaide, South Australia, when a violent hit sent him flying into the water.

Drummond told 7News that "the shark just came up and hit me from underneath. I suddenly felt my ski rise above the water, and before I knew it, I was in the air before falling into the ocean."

Drummond was rescued by competitors, who gave him a ride back to shore on another surf ski.

When Drummond's surf ski was found, he saw that a shark had bit a hole in the seafloor not far from where his feet had been.

A shark tooth left in the ski has been sent for analysis to determine the type of shark it came from.

UPI