Scoring in every quarter and converting on third down 11 of 14 times, the Cougars not only played consistently well for four quarters, but they also displayed the offensive balance they've been searching for all season. They ran for 282 yards and passed for 217, their highest yardage total, 499, since putting 514 on UTEP in the New Mexico Bowl last year.
And leading the way was the swashbuckling Nelson, now 2-0 as a starter, 1-0 as a reliever, and quickly establishing himself as the leader of a team that a month ago was seemingly left for dead after a 44-point loss to Utah.
"He has changed their team since he has taken over," marveled OSU coach Mike Riley. "He is tough to deal with."
Nelson was the game's leading rusher with 87 yards on 12 carries, often breaking containment and picking up key first downs to keep drives alive. He completed 17 of 27 passes for 217 yards and three touchdowns, but also made a critical mistake that allowed OSU to get back in the contest.
Nelson floated a pass toward Ross Apo that OSU's Jordan Poyer picked off and returned 51 yards to tie the game 14-14 heading into halftime.
"It was a poor decision, but he made a lot of great decisions as well," Mendenhall said.
"Man, that pick-six was rough," Nelson said, assessing his play and giving himself a grade. "B-minus. I got a little bit better today."
Most of the Cougars did, really, with Cody Hoffman posting a career game in front of hundreds of supporters from his hometown of Crescent City, Calif., just across the Oregon border. He had 162 receiving yards and a touchdown grab on nine catches, a couple of them circus-like.
Running back Mike Alisa took another step toward claiming the bulk of the carries, pounding out 84 yards and a touchdown on 20 attempts despite having a 30-yard touchdown run called back because Marco Thorson was flagged for holding.
"We certainly had our share of miscues or mistakes that kept the game competitive," Mendenhall said. "I like the way our team responded, especially in the second half, and offensively by moving the football and the defense creating turnovers."
Kyle Van Noy and Brandon Ogletree had interceptions, and Ogletree forced a pair of fumbles. Oregon State's first three possessions of the third quarter ended with turnovers, and although the Cougars could turn them into only three points, it clearly kept the home team from seizing any momentum.
About the only dim spot for the defense was the 59-yard bomb from Sean Mannion to Brandin Cooks that cut BYU's lead to 24-21 with 2:08 remaining in the third quarter.
"We just got outrun," Mendenhall said. "Oregon State had a fast guy, and we had a fast guy [Corby Eason], and their guy was faster than ours. It was a good throw and a good catch."
But it didn't derail the Cougars, who answered with the 12-play, 66-yard drive to regain their 10-point advantage. Nelson's 2-yard TD pass to J.D. Falslev capped the deal.
"I must say, it wasn't like a real stressful situation because we were running the ball well," Nelson said. "It does feel like we left some points out there, but we won."
And a month ago, after a loss to a different Pac-12 team, wins didn't appear all that probable.
BYU 38, OSU 28
R In Short • BYU defeats at least one Pac-12 team for the sixth consecutive season, running past Oregon State with 499 total yards while forcing four turnovers.
Key Moment • The Cougars answer a 59-yard OSU touchdown pass late in the third quarter with a 12-play, 66-yard touchdown drive to regain their 10-point lead.
Key Stats • The Cougars convert 11 of their 14 third-down opportunities and rush for 282 yards.