He threw a 35-yard touchdown to Mitchell Juergens with 45 seconds left to give BYU its second last-minute victory in as many weeks. The Cougars defeated No. 20 Boise State 35-24 as the Mangum magic continued.
"We like to have big explosive plays like that," Mangum said. "... Sometimes it's a little bit improvised on a scramble. Sometimes it's designed. More than anything, I just do my best to make the right decision."
BYU (2-0) trailed for most of the game. Mangum was far from perfect, completing 17 of 28 passes for 309 yards and throwing two interceptions. But the deep ball worked for him, and he came through when it mattered most. Jeurgens caught the game winner in the middle of three defenders after Mangum scrambled out the pocket.
Mangum was making the first start of his career after another shocking victory last week. He introduced himself to the college football world after senior Taysom Hill was lost for the season with a Lisfranc sprain in his foot.
Mangum played well in relief, but he snatched a place in BYU lore with a 42-yard Hail Mary touchdown pass to Mitch Mathews with no time remaining to beat traditional power Nebraska on the road.
"First start, to beat that team in front of a home crowd after a week ago and the Hail Mary, I don't know where you go from there. But I'm really proud of him," BYU coach Bronco Mendenhall said.
Mangum struggled on intermediate passes much of the night, but the long ball was his friend. That and the fact he never lost confidence or got trigger-shy. An 84-yard touchdown pass to Juergens on the first drive of the game was the fifth-longest in school history and the longest since 1996. Mangum had three passes go for a combined 189 yards.
"He said, Sorry for making it so close," said Mendenhall.
Boise State quarterback Ryan Finley threw for 297 yards, one touchdown and three interceptions. Running back Jeremy McNichols finished with 95 total yards and two touchdowns for the Broncos (1-1).
"It hurt. We got to go back and fix everything," McNichols said.
The first half could be viewed in one of two ways: brilliant play by both defenses or a pair of sloppy offenses. The two teams combined for 10 punts and three interceptions in the first 30 minutes. BYU scored on its opening 75-yard drive then totaled a combined 87 yards on its next seven drives.
The BYU run game was nonexistent in the first half, totaling minus-14 yards on 19 carries. But the Broncos front-seven softened in the second half and Adam Hine bullied his way to 93 yards and a touchdown on 19 carries.
Boise State led by 10 going into the fourth quarter, but BYU scored 21 points unanswered. The Cougars defense played their best stretch of the game in the fourth and forced two punts and picked off two passes
"How we walk away from this game will be extremely important to this football team," Boise State coach Bryan Harsin said. "That's really my message to them. We've lost games before. Teams across the country lose games. How you recover is really the important key."
BYU rides late-game magic again for the win
For the second straight week, BYU needed a desperation pass and catch to pull off a miracle win, this time over Boise State.
BYU coach: 'I'm impressed by my team'
BYU coach Bronco Mendenhall discusses his team's second straight emotional win, a 35-24 victory over Boise State.