OKEMO, Vt., March 28– Olympic halfpipe medalist Shannon Dunn (Steamboat Springs, CO) and Canadian ‘pipe specialist Mike Michalchuk picked up the keys to a new Chevy S-10 truck Sunday as they emerged on top in the innovative Super Prix covering results from the X-nix U.S. Snowboard Championships and the $370,000 Chevy S-10 U.S. Snowboard Grand Prix. Meanwhile, two relative unknowns — Ryan Neptune (Boise, ID) and Amy Johnson (Bondville, VT) — won the first national snowboard cross championships.

On the final day of the X-nix championships at Okemo Mountain, Neptune — who won the SBX at the final Grand Prix stop last month at Sunday River, Maine — beat Seth Wescott (Farmington, ME), Jeff Greenwood (Granby, CT) and Canadian Jasey Jay Anderson down the hill for the men’s snowboard cross title. A short time earlier, Johnson took advantage of a collision in the final rollers to pull past Dunn and Kelly Clark (Dover, VT) for the women’s crown. Neptune and Johnson also pocketed $1,700 apiece.

SBX, which was added to the Grand Prix lineup this season, is like roller derby on snow. Generally, four to six riders start together and make their way through a course that includes bumps, berms, turns and rollers (jumps) — and the first rider across the finish wins.

“I thought I had it the course pretty well dialed-in,” said Neptune, 24, who owns his own welding business, Neptune Industries, in Boise. He seldom rides on his own, he said, conceding he only competes because his snowboard company pays the entry fees. “I didn’t think there was going to be any trouble because there were so many places to pass.

“I was fourth last out of the gate but I had no worries because it’s all straight,” he said. “Everyone speed-checked and I just kept going. It’s not that I like going fast but my comfort zone is there. You snowboard for 14 years and you get that.”

He breezed to the title when Greenwood, who won the slalom championship Thursday, started to close but misjudged a jump in the final rollers and went down, suffering a bloody nose as a knee hit him in the face. “I was the first one out of the five series of tabletops. He passed me because I went too high in the air, then I caught up to him and we were dueling, and I thought, ‘I’ve got to go 100 percent,’” Greenwood said. “I should’ve pre-jumped it, but I landed on the flat and when I went forward, I hit my knee.”

In the women’s event, Johnson said she was about 10 feet behind Dunn and Clark when they rode into each other, also in the final rollers. “They turned into each other from opposite ways,” the new champion said, “I was close enough that I was able to pass ‘em. I said, ‘I’ve got to take this chance’ and I went by.”

The Super Prix was a tally of a rider’s three best results in the three Grand Prix events (Mt. Bachelor, Ore. in December, Copper Mountain in January and Sunday River in February) plus the national championships. Going into the SBX, it came down to Dunn, who never rides snowboard cross, and Van Ert, who won the GS title Friday.

“I’m a boardercross nerd,” a wide-smiling Dunn beamed as she sailed through her first heat, and she led every other run in the ladder to finals. When Van Ert failed to qualify in the semifinals — with Dunn and Johnson finishhing ahead of her in a rugged heat, Dunn earned the truck. Despite the collision, she was right on Johnson’s tail at the finish. “I don’t usually do these because of the X-factor, you never know what’s going to happen, but this was so fun. This course is really freestyle-y, so I liked that…

“I thought I was gonna make a comeback, but there wasn’t enough course left.”

In the men’s scenario, Michalchuk — with a halfpipe win and three seconds — was in control. Powers (two wins and a third) and the Canadians, Anderson and Mark Fawcett, had to win to overtake Michalchuk and take home the Chevy truck. Fawcett went out in the quarterfinals (coincidentally, in the same heat with Michalchuk); Powers missed in the semis and Anderson went into the netting high on the course in the finals while Neptune sailed off.

“I’m glad the way the Super Prix came down to the last runs,” said U.S. Coach Peter Foley. “That maintained the drama right to the end. It was pretty exciting for everyone every run. It worked out well.”

Snowboardcross Results

Men

1. Ryan Neptune, Boise, Idaho
2. Seth Wescott, Farmington, Maine
3. Jeff Greenwood, Granby, Conn.
4. Jasey Jay Anderson, Canada
5. Mike Rosengren, Bozeman, Mont.
6. Travis McLain, Snowmass, Colo.
7. Rick Bower, Park City, Utah
8. Ross Powers, S. Londonderry, Vt.

Women

1. Amy Johnson, Bondville, Vt.
2. Shannon Dunn, Steamboat Springs, Colo.
3. Kelly Clark, Dover, Vt.
4. Ellen Grimnes, Kingfield, Maine
5. Claire Cetera, Sun Valley, Idaho
6. Sondra Van Ert, Ketchum, Idaho
7. Jolene Gembarowski, W. Brattleboro, Vt.
8. Karla Gembarowski, W. Brattleboro, Vt.