"It was also really exciting to see her keep up in swims with 23- and 24-year-olds including a couple of Aussies," said Corrin snr.
"But we are also well aware she is only 14, we don't want to go silly about all of this. We need to keep our heads on, and make sure she doesn't overtrain at that age."
Corrin snr, a regional manager for a grain company, is unsure where his daughter's sporting prowess comes from. "There's no real family history to point to," he says.
"She's always been a very competitive child, always likes to win, and I don't see anything wrong with that.
"Yes, participation is important, but we also think kids have got to learn to win and lose and sometimes I think we [society] have lost that.
"She has a high level of skills and is extremely fit. I used to play sport but not to any levels, [wife] Suzanne was into competitive horse riding.
"Olivia doesn't have a huge stature and if anything is a bit smaller than many top athletes. She's just got a big ticker."
If the family are perplexed by the genes history, young Corrin increasingly knows where she is heading.
Major school exams are approaching so sport will be more focused. Last weekend's remarkable success means surf lifesaving rather than triathlons is even more certain to be the winner.
"I don't like to boast about my achievements," says the quietly spoken Gisborne Girls High School student. "I guess at the moment I'm just another 14-year-old girl, and I like to keep quiet although when people congratulate me it does feel good.
"I like to think I have natural ability but training is a big part - I wouldn't go into something without always training to my best. Whatever results come from that, I'm happy with."
One of her first coaches was Cory Hutchings, the former world surf lifesaving Ironman champion.
"I can't really remember what he said but I'm sure he would have told us to give it all, that we have to keep going, and encouraged us to do our best. I like to go hard every time I race, give it all I can," Corrin said.
It's no surprise that Corrin spends any spare time at the beach with her boards and friends. Her major aims are to represent New Zealand at surf lifesaving world championships, and try Australia's professional scene.
"Australia sounds pretty cool ... I like hometown Gisborne but it would be interesting to see what it was like being part of another club, to see if Aussie would suit me."