It takes something special to stagger John Lister, but he has been rocked by Lydia Ko's success.
He has played practice rounds with her and watched her progress and been amazed by her year so far.
Her victory in the Canadian Open crowned an unprecedented run for the teenager in New Zealand women's golf history. "Age doesn't come into it," said Lister. "We have never had a female golfer at this level. Never, not even close."
Amateurs and others in the early days had made their mark and in recent years Marilyn Smith and Lynnette Brooky had competed strongly on the international circuit, "but they can't hold a candle to this girl".
"Really, what Lydia is doing right now is she's dominating amateur golf more than Tiger did in his day. That's how big this is," Lister said.
"Tiger never won a pro tournament when he was an amateur.
"Just this year to win a tournament on the ladies European tour, win the Australian, New Zealand and US Amateur and an LPGA event it is mega, it is staggering. It is fantastic, stunning."
Lister, 65, a winner on the PGA Tour, has seen a few things in his time and is enthralled by Ko's unprepossessing charm.
Her course management was equally crisp, he said. She had picked up strategy very quickly while he was still trying to get a few of his pupils to understand those techniques after 20 years.
Ko might not look a natural athlete but she had worked hard and her game and physique were still developing.
Lister last watched her play live this year at Muriwai, then in the tournament at the Hills in Queenstown, and was highly impressed.
"She still has areas to improve on. She'll get to be a better putter in time, that's a bit variable, and her pace of play could improve," he said.
But Ko was a young woman and was going to be making a lot of decisions - she had to have the freedom to do that.
Her potential was crystal-ball territory. "You never know what could happen, she could snap a tendon tomorrow and it's all finished," said Lister.
"Boys might become important and it's all finished then, as well.
"It's foolish to predict anything and all that does is put onus on someone that's not needed. She just needs to enjoy it.
"Tiger has 14 majors and we all said, including me, he will steamroll Jack [Nicklaus'] record and now it looks like he's not going to get there."
Ko was a class above the others. She was getting stronger and statistics showed she was averaging 245m with the driver.
Everything about her game was astonishing and Lister doubted whether "we'll see anything like it again in New Zealand women's golf".