Sam Dillon says instinct kicked in when he realised a fellow surfer had been bitten by a shark off Windang Beach.
"It was just one of those things," he said.
"You hear about the stories all the time, and you do what you can to stop the bleeding and make sure someone's alright."
Another surfer, Peter Coombs is a friend of the victim, and also came to his aid.
"I don't know (if it was just instinct)," he said. "It's starting to sink in. It's weird. I didn't really think about it too much then.
"When I heard him first start yelling out and waving, I thought something was wrong, but I didn't know what.
"You can see the chunk in his foot - you can tell it's a shark bite."
The surfer, Albion Park resident Wil Schroeter, was bitten by the shark off Windang Beach on Friday morning.
The 59-year-old man, who reportedly regularly surfs at the spot, was bitten on the foot after 8am while in the water near the entrance to Lake Illawarra.
Mr Schroeter paddled himself to shore, where he was assisted by an off-duty Wollongong City Council lifeguard and other people on the beach, who applied a tourniquet to stem the bleeding.
Mr Coombs said he didn't see the shark, but heard the victim yelling out from about 60 metres away.
"I paddled in and ran up the beach, and met him at the beach," he said.
"A few guys came along and we put him on his board and lifted him up to here (to the surf club).
"I could see the big bite on his foot.
"We just got our leg ropes off our boards and tried to stop the bleeding as best we could," Mr Coombs said.
Mr Dillon helped apply the tourniquet.
"Yeah, an initial couple over the wound, and then just put another one on further up his leg," he said.
Mr Dillon said he doesn't know the victim personally.
"We didn't really see anything in the water, we just saw Wil coming back in," he said.
"We just went up there and did what we could. We could see there was a wound, so we did what we could to try and stop the bleeding."
Officers from Lake Illawarra Police District attended with NSW Ambulance paramedics, who treated the man for lacerations to his foot.
Mr Schroeter was bleeding a lot, but that was brought under control.
NSW Ambulance Illawarra district Inspector Terry Morrow said they were called to the incident about 8.45am.
"Apparently he was sitting on the board with both legs dangling over the surfboard, and all of a sudden he felt a tug on his leg," Insp Morrow said.
"He looked down and there was some blood oozing from a wound.
"He made his way into the shore, and when he reached the shore the surf lifesaving people here put him on a surfboard and brought him into the surf club."
Insp Morrow said it appeared it was a small shark, due to the size of the injury.
"It's incorporated a bite mark on the top arch of his foot and underneath his (left) foot that has involved some ligament damage.
"The teeth have gone into the bone joint in the ankle."
Insp Morrow said the victim had been "very lucky", and was in "good spirits".
"I think if it had been a larger shark, it may have taken his whole foot off," he said.
"However, it appears the way the shark has bitten the ankle joint, it's let go as soon as it's got hold of something that's a little bit large."
Mr Schroeter was taken to Wollongong Hospital for exploratory surgery.
According to police, his injuries are not considered life-threatening.
Wollongong City Council's beach services operations manager Paul Dreghorn said they had launched their jet ski from Port Kembla to look around the area.
"We'll keep the beach closed until further notice, until we're sure there's no more issues with sharks around here," he said.
Mr Dreghorn couldn't confirm which type of shark it may have been.
He also said there wasn't a history of shark attacks at Windang Beach.