Beijing, China - Snowboarder Chloe Kim has continued her winning streak to secure back-to-back Olympic golds for the USA.

Kim dominated the women's halfpipe at the Beijing Winter Games, finishing almost four points ahead of Queralt Castellet of Spain, and becoming the first woman to win two halfpipe snowboarding gold medals in Olympic history.

The American scored 94 on her first run, blurting out "Oh my God" as she came into the finish on Thursday morning.

"I was so proud of myself. I had the worst practice, ever," the 21-year-old said. "I probably landed my run twice when I’m used to landing it eight times, normally, and so that puts you in a weird headspace."

While her score of 94 stood throughout, she said the win was not comfortable.

"The girls are killing it, and they’re progressing at such a quick rate. I find it inspirational that everyone’s out progressing the sport," she added.

"At the last Olympics, you didn’t see that many 1080s, and now everyone is doing a 1080. That’s quite the improvement, and it’s such an honor to be part of this sport and help progress women’s halfpipe snowboarding."

Kim fell on both her second and final runs attempting to land a 1260.

"It was worth it for sure, 1000%," Kim said. "That’s what keeps me going. I wish I’d landed it, but next time."

Kim's oldest competitor in the final, Castellet was the only other rider to hit a score in the 90s, with a best run of 90.25.

The 32-year-old finally managed to collect an Olympic medal at her fifth attempt.

"My first Olympics I was 16 years old. I was far away from even thinking that the podium was a possibility," Castellet said. "I did set up a dream and my dream was to be up there... Very happy it happened today, 16 years after."

Japan's Sena Tomita took bronze with 88.25, and has become the first Japanese woman to win an Olympic medal in halfpipe.

"I am really happy that I got the first one for Japan," she said, adding that all the athletes were "very aggressive" during the competition.

"And in that kind of competitive environment, I got a medal. That has given me a lot of confidence," Sena said.

It was a different fortune for her younger sister Ruki, who fell in her two first runs. She was able to put down a run in her final attempt to finish fifth.

Two-time halfpipe world champion Cai Xuetong of China was fourth.

Pyeongchang 2018 silver medallist Liu Jiayu fell in both her first runs, and placed eighth with 73.50.

Kim's teammate Shaun White survived a scare of falling in his first run of the men's snowboard halfpipe qualifications on Wednesday to make the final in his fifth and final Olympic Games. He will also aim for gold later on Thursday.