Sage Kotsenburg of the USA celebrates after winning the men’s Snowboard Slopestyle final at Rosa Khutor Extreme Park at the Sochi 2014 Olympic Games, Krasnaya Polyana, Russia, 08 February February 2014. EPA/JENS BUETTNER

KRASNAYA POLYANA, Russia — The United States is officially on the Olympic scoreboard, as snowboarder Sage Kotsenburg, a charismatic 20-year old from Park City, Utah, put together a near-flawless run in the finals of the men’s slopestyle event and won gold here Saturday afternoon.

In an event that many felt would be dominated by the talented Canadians, even Kotsenburg seemed surprised he was even in position to medal. After the semifinals Saturday morning, he tweeted: “Whoa how random is this I made finals at the Olympics!!!”

Later in the afternoon, Kotsenburg held a strong lead over the field after the first run. His impressive run was good enough for a 93.5. No one else was better than 85.5 after one trip down the mountain. He was the third rider in the event’s final run and impressed again, scoring an 83.25. He then had to hold his breath as he watched the final nine competitors try to top his mark.

One by one they came down, the top snowboarders in the world flipping, spinning and in some cases, falling. With such a high score to beat, many had to go big and it cost them.

Kotsenburg’s 93.5 was the second-highest mark of the event’s three rounds. Norway’s Staale Sandbech posted a 94.5 in the qualification round on Thursday.

With only five riders remaining, Sweden’s Sven Thorgren represented one of the biggest threats. He put together a nearly flawless run, lifting his hands in celebration when he landed his third jump. When he reached the base of the hill, Kotsenburg was the first to offer him a congratulatory hug, even before the score was announced. Judges gave Thorgren an 87.5, which momentarily put him in third place.

A few riders later, Norway’s Sandbech put together a near-perfect run of his own. Judges gave him a 91.75, good enough for silver.

The Canadian team entered the finals with three legit medal contenders. None was among the top four riders after the first run of the finals. Mark McMorris, a medal-favorite entering the Olympics who’d been riding this week with a broken rib, nailed a pair of triple corks in his second run of the day. Judges only awarded him an 88.75, though, which momentarily put him in second place but well behind Kotsenburg. Considered a gold medal-favorite entering the event, McMorris eventually finished in third and took home bronze.

His teammates Maxence Parrot was 5th (87.25) and Sebastien Toutant was 9th (58.5).

The slopestyle event — a mountain course that combines rails and big jumps — was making its Olympic debut at the Sochi Games. Snowboarder Shaun White was originally scheduled to compete in the men’s competition, but he pulled out of the event earlier in the week to focus on the halfpipe.

More Olympic coverage from the Post:

American Sage Kotsenburg wins snowboard slopestyle gold

Mike Wise: Flag-bearer’s Olympic quests

Sally Jenkins: Hotel complaints aren’t the half of it