LINCOLN, Neb. (AP) No matter how many games Tanner Mangum plays for BYU, it will be hard for him to top what he did in his first one.
Playing in the college football cathedral that is Nebraska's Memorial Stadium, and having replaced injured star Taysom Hill early in the fourth quarter, Mangum heaved a 42-yard touchdown pass to Mitch Mathews with no time left for a 33-28 victory Saturday.
''It was a good welcome to college football,'' Mangum said.
The stunning last play spoiled the debut of new Nebraska coach Mike Riley. While a celebration erupted on the BYU sideline, Riley raised clenched fists over his head and looked down as his headset slipped backward.
Mathews jumped around at midfield as teammates mobbed him after the play stood up to a video review. A half-hour after the game, hundreds of joyous BYU fans still congregated in the south end zone near where Mathews came down with the ball.
''I had to come down with it,'' Mathews said. ''I had to come down with it for my guys. Sometime you have to do what you have to do, and that's catch the rock and win the game. I didn't know I scored right away because I was under a pile of people. Nick Kurtz was laying on me and was screaming.''
The victory came with a heavy price. Hill sustained a season-ending injury for the second straight year. Coach Bronco Mendenhall said Hill fractured a foot on a 21-yard touchdown run in the first half. He went to the locker room and missed two plays before returning, then left again after getting hit hard on an 8-yard run in the fourth quarter.
''The training staff said they've never seen anyone go back and play in the same game once that's happened,'' Mendenhall said. ''He allowed us to stay within striking distance.''
Making Mangum's dramatic play even more remarkable was that he returned from his two-year LDS mission in June. Mangum hadn't played in an organized football game since 2012. He finished 7 of 11 for 111 yards and is the presumed starter when the Cougars host Boise State next week.
''I'm amazed that Tanner Mangum, just two months off his mission, coming in and being able to help our team win,'' Mendenhall said. ''I was just proud of the way he was able to lead our team on the big stage, in an historic stadium, finding a way to pull it out.''
Trevor Samson's 35-yard field goal pulled BYU within 28-27 with 7:57 left, and after Drew Brown missed a 41-yard field goal for Nebraska, the Cougars started their final drive from their own 35. There were 48 seconds to play.
Mangum faced four-and-3 from the Nebraska 42 when he launched his winning pass against a three-man rush.
''I rolled out and threw it. It wasn't my best ball,'' Mangum said. ''Came out a little wobbly. But I was just glad it got there. Mitch made a heck of a catch and was able to fall in for the score.''
The Huskers lost their season opener for the first time since 1985, ending the nation's longest streak.
Riley, in his 41st year in coaching, said he couldn't remember ever losing a game the way he did his first one at Nebraska.
''I initially thought he was not in the end zone, but I had a really bad view,'' Riley said. ''I saw the official raise his hands right away, so I knew.''
Tommy Armstrong Jr. passed for 319 yards and three touchdowns, his last one going 9 yards to Trey Foster for a 28-24 lead, and Jordan Westerkamp caught seven balls for 107 yards and a score.
This opener was long anticipated by both teams. Riley, who spent the last 12 years at Oregon State, was athletic director Shawn Eichorst's surprise hire last December after Bo Pelini was fired.
BYU, meanwhile, came in looking to continue raising its profile as an independent and was coming off three wins last year against opponents from Power Five conferences. The Cougars play Boise State at home next week, then play back-to-back road games against UCLA and Michigan.
Each team was without players who were suspended for disciplinary reasons. Among the five missing Huskers were linebacker Michael Rose-Ivey, cornerback Jonathan Rose and tight end Cethan Carter. Among the suspended BYU players were defensive lineman Tomasi Laulile, free safety Kai Nacua, linebacker Sione Takitaki and wide receiver Trey Dye.
AP college football website: collegefootball.ap.org