Kira Kimura won Japan's first-ever men's snowboard big air Olympic gold at the Milan-Cortina Games on Saturday, producing a stunning final run under pressure to edge out compatriot Ryoma Kimata and defending champion Su Yiming of China.

The 21-year-old Kimura, 11th at last year's world championships, topped the leaderboard after an impressive 89.00 in his first run.

But he flunked his second effort, meaning he had to produce something special in his third run – and he did not disappoint.

"I've devoted a lot of time to snowboarding this year," said Kimura.

"My family, coach and everyone around me gave me tremendous support, so I'm truly delighted to have achieved this result and prove the doubters wrong."

Meanwhile, Su secured China's first medal of the Games with a bronze in the event.

With consistency proving decisive in the high-stakes showdown, 21-year-old Su struck a careful balance between ambition and control after rebounding from a fall in qualification to reach the final.

"I'm just really proud of myself to deal with such big pressure and still be able to land my tricks. Finally, I have every single colour of medals," Su said.

"I'm truly delighted to wear the national colours, standing here to secure our nation's first medal."

He opened with a clean and confident 1980-degree spin, earning 88.25 points, but could not fully capitalise thereafter, touching down with his hand on both his second and third runs for scores of 73.75 and 80.25 respectively.

Japan and China are the dominant forces in men's big air, but Japan had never previously won a Olympic medal of any colour in the discipline since big air made its Olympic debut in 2018. (AFP/Xinhua)