BOISE, Idaho >> The Mountain West football championship game was decided on fourth down — two of them, in fact.

No. 19 Boise State stuffed Hawaii on the goal line early in the second quarter Saturday afternoon at Albertsons Stadium, then the Broncos stunned the Rainbow Warriors with a 36-yard touchdown pass on a fourth down of their own.

Those two plays put the Broncos in control — and they rolled from there for a 31-10 victory.

>> Click here to see photos of the game between Hawaii and Boise State.

“The fourth-and-1 at the goal line when we didn’t get anything, I think that was a big turning point,” Hawaii coach Nick Rolovich said.

Hawaii actually had taken a 6-3 lead moments before that play, but Boise State was offside on the field-goal attempt. Rolovich decided to take the points off the board and put the offense back on the field for fourth-and-goal from the 1-yard line. The Warriors already had converted a fourth-and-1 on the drive, and another fourth-and-1 in the first quarter.

“I didn’t think field goals were going to win this football game,” Rolovich said. “…. I thought we had to play aggressive to win this football game vs. this team.”

Quarterback Cole McDonald ran a keeper to the right, but the play went awry at the snap. Boise State senior nose tackle Sonatane Lui had figured out the Warriors’ snap system and timed that snap so well that he appeared offside to the naked eye. On replay, it looked like Lui might have been just barely onside.

“They didn’t call it,” Boise State coach Bryan Harsin said, as the question was presented to Lui.

“Sometimes,” said Lui, the game’s defensive MVP, “the refs aren’t in your favor and sometimes they are. … I timed it up and I guess he was trying to trick me because he said, ‘Set, hut,’ and he didn’t snap the ball (immediately).”

Lui busted the play and junior linebacker Riley Whimpey helped him tackle McDonald short of the goal line with 9 minutes, 35 seconds left in the first half. It was still 3-3.

Boise State’s struggling offense faced its own fourth-down decision late in the first half. The Broncos had fourth-and-4 at the Hawaii 36 — too far out for their field-goal team.

Hawaii seemed to expect a quick throw, bringing nine players to the line of scrimmage and leaving two shallow safeties less than 10 yards from the line. That gave the Broncos man coverage on the outside, and that’s what they wanted.

Left tackle Ezra Cleveland and tailback Andrew Van Buren picked up the blitz, giving quarterback Jaylon Henderson just enough time to roll left and hoist a pass down the left sideline to sophomore wide receiver Khalil Shakir for the 36-yard touchdown.

Shakir used a double move to get behind Kai Kaneshiro.

“It was a great call by Boise,” Rolovich said.

Like Hawaii, Boise State came into the game thinking aggressively, Harsin said. The Broncos went for the touchdown when most teams would have just tried to get a first down.

“You’ve got an opportunity to score — doesn’t matter if it’s fourth-and-8 or first-and-10. Score,” Harsin said.

That throw sparked Henderson, who finished 20-for-29 for 212 yards and two touchdowns with 51 rushing yards and another TD. He was named the game’s offensive MVP.

Just before the touchdown drive, true freshman Hank Bachmeier — who started seven of the first eight games for Boise State before injuries derailed him — was warming up vigorously on the sideline. Harsin was thinking of inserting Bachmeier, the coach said, but that proved unnecessary.

Henderson tossed another 36-yard touchdown pass 53 seconds after the first to give Boise State a 17-3 lead at halftime.

“The momentum swung in our favor,” Harsin said, “and you kind of ride the wave there a little bit.”

A wave that started with a fourth-down stop.