Boise State did not score on offense, but Michael Atkinson's interception return for a touchdown was all the 24th-ranked Broncos needed to eke out a 7-6 victory over the BYU Cougars.
Both offenses were held off the scoreboard until freshman backup quarterback Taysom Hill led BYU on an 11-play, 95-yard drive late in the fourth quarter.
Hill ran in for a 4-yard score with 3:37 remaining, and BYU head coach Bronco Mendenhall decided to attempt a two-point conversion rather than kick the game-tying extra point.
Hill, pressured by Atkinson, rolled to his right and was looking for tight end Kaneakua Friel, but senior linebacker J.C. Percy knocked down the pass, and the Broncos ran out the remaining time to win their second straight game.
"I wanted to win," Mendenhall said. "We had momentum for the first time in the game, moving the ball offensively. We wanted to capitalize on it. I'd do it again."
The usually high-octane offense of Boise State (2-1) went 0-for-5 on fourth down tries and gained just 261 yards.
"I'm ecstatic for what happened on defense," Boise State coach Chris Petersen said. "We have to go back to the drawing board on the other side. That happens sometimes."
But the Cougars (2-2) gained a mere 200 yards themselves and turned the ball over five times to drop their second straight game.
D.J. Harper was the lone bright spot for Boise State's offense, gaining 112 yards on a workmanlike 31 carries. Joe Southwick threw for 145 yards on 15- of-25 passing, hitting Matt Miller seven times for 75 yards in the win.
Hill finished with 42 yards on 4-of-10 throws in relief of Riley Nelson, who was intercepted three times on just nine attempts. Hill also led the Cougars with 72 yards rushing on 12 carries.
After a scoreless first half, Atkinson made the play of the game just 1:36 into the third quarter.
On 3rd-and-6 from the BYU 38, Nelson was looking for Ross Apo on a quick slant. Atkinson dropped slightly back into coverage from his defensive tackle spot and made a leaping interception. The 6-foot, 306-pound senior rumbled 36 yards the other way with what proved to be the game-winner.
Riley was intercepted again on the ensuing drive, and though the Broncos wound up punting, they pinned BYU at its own 1-yard line.
Michael Alisa fumbled on the next play of the ensuing drive, but the Cougars' defensive front stepped up with a goal line stand. Harper was stopped twice for a loss and was pulled down a yard short of the goal line on third down.
On fourth down, Southwick was halted in his tracks on a quarterback sneak, and BYU took over on downs.
A series of punts ensued before BYU took over at its own five midway through the fourth quarter. Hill completed a 21-yard pass to Richard Wilson to get the Cougars moving, and kept the drive alive with a 6-yard completion to Cody Hoffman on 4th-and-3 from the Boise State 18.
Hill ran for an 8-yard gain before his touchdown run preceded Mendenhall's interesting decision to go for two.
The Broncos' special teams failed them in the first quarter, as Michael Frisina missed a 33-yard field goal midway through and a fake punt came up two yards short to give the Cougars great field position. On 4th-and-2 from their own 22, the Broncos snapped the ball directly to the upback, who was stuffed by Ezekiel Ansah for no gain.
BYU reached the 2-yard line on the second play of the second quarter, but an illegal blocking penalty negated a first-down run. On the next play, from the 17, Nelson threw into double coverage and was picked off by Jamar Taylor.
Boise State turned the ball over twice on downs in BYU territory later in the half to keep it 0-0 going into the break.
Boise State also failed to score an offensive touchdown in its season-opening loss at Michigan State ... Boise State has not lost a home game in September since 2001 ... BYU went 2-for-12 on third-down conversions ... This was the first of a 12-year series between the programs.