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By Audrey Cleo Yap

Climbing phenom Ashima Shiraishi took first place in the female sport category at the 2017 USA Climbing Sport & Speed Open National Championships last weekend.

The 15-year-old reigning world champion was only one of two to complete the women’s final climb — called a "problem" in climbing parlance — in the competition, held March 10 through 11 in Denver.

Shiraishi told NBC News that maintaining her top position round after round to finish in first was a nerve-racking experience.

“As I was climbing, I had to focus on pacing myself and just relaxing and focus on the climbing instead of falling down and not being able to control my nerves,” she said. “Once I latched the finish hold, I was so relieved and just happy. I couldn’t really believe it.”

RELATED: How 15-Year-Old Ashima Shiraishi Became the Face of Pro Rock Climbing

The event, held at Movement Climbing + Fitness Denver, drew a record number of competitors, according to USA Climbing. A total of 177 climbers competed in two categories, sport (119 climbers) and speed (58 climbers).

Ashima Shiraishi took first place at the 2017 USA Climbing Sport & Speed National Championships held March 10 and 11.Greg Mionske Photography

While this was Shiraishi’s first time competing at Sport Open Nationals, it wasn’t her first time competing against adults, which she has been doing since age 7.

“I didn’t feel any major differences, even though I was competing against people way older than me. I treat each competition the same way no matter how big it is. For this one, it was no different,” she said.

Born in New York City, Shiraishi started climbing at age 6 when she saw people climbing in Central Park. In March 2016, days before her 15th birthday, Shiraishi successfully ascended (or “sent”) Horizon on Mt. Hiei in Japan, becoming the first woman and youngest person ever to solve a V15 boulder problem, considered the most difficult type of problem in the sport’s grading scale.

She is also the world’s youngest person to send V10, V13, and V14 boulders, which she did at ages 8, 10, and 13, respectively.

Last July, Shiraishi landed in the ER after a belaying accident where she fell four stories at an indoor climbing gym. She survived with a few bruises on her back and went on to win Youth Nationals a few days later.

“I feel like that injury made me think about how valuable climbing is to my life. I think it made me grow as a climber, but it didn’t make me scared of climbing or scared of falling,” she said.

Shiraishi will be spending her spring break next month in Spain, where she will attempt what she calls “some really hard problems.”

But not before relishing a little in her recent win. After finishing first in Denver, Shiraishi — along with a few fellow climbers — celebrated with an ice cream outing.

“I got a hot fudge sundae, and I got two flavors in it: peanut butter swirl and vegan carrot cake,” she said. “It was very good.”

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