With an AMA Supercross series title hanging in the balance, the last thing Chad Reed wanted to see was the teammate of his archrival blocking his path.

Yet, with seven laps left in what was shaping up as an epic battle on the Rice-Eccles Stadium course against defending champion and current series leader James Stewart, Kyle Chisholm cut between Stewart — who had just taken the lead on a jump — and Reed on a corner and effectively ended the race by creating a big gap between the two leaders.

Reed had led most of the first 12 laps of the Supercross main event, battling back and forth with Stewart and exchanging the lead several times, but found himself in trouble as they pulled away from the field and running into lapped traffic.

Trailing Stewart by just three points, Reed wanted desperately to pick up a win Saturday night and create a tie in the standings.

But it wasn't to be.

"It was a fun race," said Stewart, who won and extended his lead to an almost-comfortable six points. "The guy was on it tonight, and he made me work for it."

Reed showed he had every intention of winning from the moment the gates dropped.

"I got the hole shot and tried to put some good laps together," Reed said, "but the track kind of broke down."

Several earlier races and some rain left the dirt course choppy and slick, but after the initial charge, it was clear the race belonged to Stewart and Reed as the duo quickly put a gap between their personal battle and the rest of the 20-man field.

With passes coming on hairpin turns and triple jumps, the lead went from one rider to the other several times.

But on lap 12 and with Stewart in the lead, Chisholm — Stewart's teammate — got in the way and earned the scorn of most of the announced crowd of 40,612 by impeding the path of Reed.

"It's hard to put it into words," Reed said. "But we'll go on to next week."

Chisholm was black-flagged and kicked out of the race, but the damage to Reed's hopes had already been done as Stewart easily covered the final seven laps to pick up the win by 3.7 seconds.

David Millsaps was third, more than 31 seconds off the pace.

Though Reed didn't say anything about the on-course incident after the race, his actions were loud and clear as he gave Chisholm a long look while kicking his rear wheel at him as he passed him a final time on a triple jump near the start/finish line.

The results set up what will be a compelling series finale next weekend in Las Vegas as Reed tries to make up all six points and reclaim the championship he has enjoyed three times.

Ryan Villopoto was fourth and Andrew Short fifth in Saturday's main event.