Norimasa Hirai, the acclaimed head coach of Japan's swimming team, is widely credited for grooming Kosuke Kitajima and Kosuke Hagino into Olympic champions.

Three years away from the Tokyo Olympics, Hirai just may have another gold medalist in the works in 21-year-old Yui Ohashi, who set the national championships alight Friday after shattering the Japan record in the women's 400-meter individual medley.

Ohashi's time of 4 minutes, 31.42 seconds was 3.24 seconds faster than the old mark held by Sakiko Shimizu, who was runner-up -- more than six full seconds behind. Shimizu was last in the 400 IM final at last summer's Rio Olympics in 4:38.06.

Ohashi's record on Friday would have been good enough for a bronze in Rio and close to Maya DiRado's silver (4:31.15), earning her the opportunity to see if she can make a splash at the world championships in July in Budapest.

Ohashi did not even make the Japanese team for Rio but since last year's nationals, the Toyo University senior looks to have come into her own -- and then some.

"I couldn't let up. I went to Spain (in February) and trained hard at altitude," Ohashi said. "My times there were good, and I was training with the determination to go to the worlds. I really pushed myself there and I think that's what led to this record."

"I finished third here last year but didn't make the cut. So I spent the past year making sure to qualify this year. Last year's nationals were the turning point, I think."

Take it from fellow Hirai prodigy Hagino when he says Ohashi is the real deal.

"It's great because I've found a good partner to train with now," Hagino joked. "I always had to train for the IM on my own so welcome to her."

"With the time she had today, she can medal at the world championships. We've been training hard and she was in good condition going into the Konami Open (in February). She was putting in a lot of work at altitude and I hope we can continue to spur each other on."

Ohashi's upside perhaps was hidden in her ultrathin build. In her first year at university, she was battling anemia and her 1.74-meter frame was so slight that once at her school cafeteria, she popped her kneecap bumping into a kitchen table, Hirai said.

But Hirai, understanding he had a gem on his hands, was patient with Ohashi, bringing her along slowly but surely. Ohashi started showing signs this February, when she posted a 4:35.35 to close in on Shimizu's mark which she would eventually destroy.

Ohashi kept rising as later in the month, Hirai took a team to Sierra Nevada, Spain, for altitude training where she toughed it out for five weeks with Japan's elite like Hagino.

And as it started to come together for Ohashi physically, so did her confidence.

"When I told her she could swim a 4:35, she didn't believe me and she did it," Hirai said. "I told her 4:31 for today and she managed that, too. So the next time I tell her she can do something, she better not doubt me -- even by a single percent."

"She didn't have much experience in the big meets before. And at altitude, she worked a lot on her butterfly which was never her strength. Experience and hard work is finally paying off for her."

With her pinup looks and the next games to be held in Tokyo, Ohashi appears to have shot to stardom overnight. As much as he recognizes Ohashi's talent, Hirai was already trying to temper the expectations which can spiral out of control in a country obsessed with the Olympics.

"It won't be easy for her this summer to be perfectly honest," Hirai said of Ohashi's prospects in Budapest. "Right now, I hope she can reach the final and give everyone a run for their money."

"But further down the road, with her ability to be aggressive early on, she needs to improve her butterfly and backstroke. And if she can pick up another second or two in the breaststroke, I reckon she's got a very good shot at a medal."

"She's talented, so all the more to handle her with care."

Hirai seems to have certainly won over Ohashi, just as he won the trust of Kitajima and Hagino.

"Coach is really good at motivating people. He gets me going and he's a reason why I've come this far," Ohashi said of Hirai. "For this meet, he told me to believe in myself. When I wasn't good enough to take part in last year's camp in Spain before the nationals, he told me to be fast enough to give him a selection headache for Rio."

"(The Tokyo Olympics) is still three years away, but if I can swim a 4:31 the way I did today, I think I can compete in the final. I do feel like I have taken a step forward."