ZHANGJIAKOU, China — Pure joy on the halfpipe looked like this on a sunny, windswept day at the Beijing Olympics:

— It was multinational freeskiing sensation Eileen Gu learning her gold medal was secure, then falling to her knees at the top of that halfpipe, covering her mouth with her mittens and screaming “Oh my God!”

— It was the 18-year-old superstar doing straight airs all the way down the pipe, gleefully punching her fists and poles downward as she vaulted herself above the lip, enjoying every last second of a victory run that meant nothing — and everything.

— It was Gu wearing a furry panda hat as she climbed the podium, smiling wide and belly laughing while accepting her third Bing Dwen Dwen mascot of the Olympics — one for each medal she’s won.

“I was very emotional at the top and I chose to do a victory lap,” Gu said of her breezy final ride down the pipe Friday. “Because I felt like, for the first time, I really deserved it and I really earned it.”

Gu: First Action-Sports Star to Win 3 Medals in Same Olympics

There were smiles mixed with tears as Gu mingled with her competitors, the coaches, and the media at the bottom — a huge sense of pride blended with incredible relief. Her two-week odyssey in China included 16 combined runs down halfpipe, slopestyle, and big air courses and countless more practice trips down those same icy expanses.

By winning her gold, in a state-of-the-art contest over defending champion Cassie Sharpe, Gu is the first action-sports athlete to win three medals at the same Olympics. Two were gold and one was silver.

“She has basically set a level that’s pretty unattainable for a lot of us,” said American freeskier Carly Margulies, who finished 11th.

Gu’s trip to China was about more than sports. About 30 months ago, she took a chance and made a statement when she decided to wear the colors of her mother’s homeland — China, the host country — instead of those of her native United States.

She received some love and some hate for that move. She explained it time and again: She did it to inspire girls in China. There was little in the way of winter-sports culture here when she was younger. There certainly is more now.

“We’re not here to break limits for a country, we’re here to break a human limit,” Gu said.

Rival Describes Gu as ‘a Machine’

Good intentions aside, her trip to the Olympics was ultimately destined to be gauged, at least on the outside, by how she did on the slopes. Yet again, with the pressure on and the world watching, Gu delivered. With her latest win, she stayed undefeated on the halfpipe this season.

‘“She’s a machine,” Sharpe said.

With winds gusting left to right on a 3 degree F (minus 16 degree C) day, Gu put this contest to rest on her first run. It included a pair of 900-degree spins in different directions, each frosted with full, second-long reaches downward to grab her skis.

Gu scored a 93.25 for that, then on her second run, she scored two points better.

She increased the difficulty on her final jump, going for back-to-back “alley-oop” flat spins in which she starts her spin twirling up the halfpipe even though she’s traveling downhill. She landed both jumps without even a hint of a bobble.

A year ago at the Winter X Games, Sharpe fell hard and tore up her left knee. On Friday, for only the second time in her career, she landed two 1080-degree spins in the same run.

Her 2-3 finish, along with teammate Rachael Karker, marked another beautiful day on the halfpipe for Canada. It was that country’s best freeskier, the late Sarah Burke, who pushed hard to get women included in halfpipe skiing, and then to bring the sport to the Olympics for the 2014 Sochi Games.

In a twist that feels like something more than just mere happenstance, the sport’s original star, Burke, and its newest one, Gu, share the same birthday: Sept. 3.

In an interview last year, Gu spoke about making a wallet out of duct tape for a sixth-grade art project. Across the front, she wrote “Celebrate Sarah,” a tribute to the pioneer who had died in a training accident in 2012.

“Even if I’m terrible at art,” Gu said that day, “I can still express myself to the best of my ability.”

As Gu prepared to head down it for the first time of her last event, she placed her hands on her hips and closed her eyes, then repeated one sentence three times.

“I said ‘My name is Eileen Gu,” she told reporters as tears welled up in her eyes, “and I’m the best halfpipe skier in the world.”

After the pep talk, she pulled down her goggles, took off down the hill and proved that one more time.

Medal Standings