After the Cougars' 38-28 setback to the Horned Frogs Friday night, Nelson admitted he played poorly in two quarters.
"This one hurts because I couldn't have played worse in the first half," he said. "I held on to the ball too many times. I can't take sacks and I had turnovers. I feel really disappointed in my performance in the first half."
Nelson threw a pair of interceptions in the first half — including one in the end zone — and completed only 6-of-15 passes. But he did have a 22-yard touchdown pass to Michael Alisa.
For the game, he completed 15-of-29 for 215 yards. Nelson also rushed 23 times for 84 yards.
He also played with a flair, high-fiving the official after barreling into the end zone on a run for a two-point conversion in the final two minutes of the game.
"I don't think I've ever high-fived a ref before," Nelson said.
Coach Bronco Mendenhall was impressed with Nelson's ability to run and his leadership.
"If you just watched him on the two-point play, anyone who wonders who he is, I don't think they should," he said. "That guy is one fierce competitor and he is a great leader. Our team loves him … He's a warrior."
"I trust Riley," said wide receiver JD Falslev. "He has more heart than anyone I know. I love his heart. I love his determination."
BYU put up 28 points, the most it has scored against TCU since scoring 27 in 2007, which was the last time the Cougars defeated the Frogs.
"Their quarterback was hard to handle," said TCU coach Gary Patterson. "He moved the ball around and really did a good job at times, in scramble situations."
Still, Nelson wasn't satisfied. "We left points on the field," he said. "It's really frustrating."
It was on third down, so that penalty extended the Frogs' drive that culminated in a field goal.
"I thought it was clean play," Mendenhall said. "I thought it was a great play."
"That's just instinct," Uale said of the hit. "I thought it was a great play but you never know if you're going to get called or not. You just got to play football and not worry about what the refs are going to do or let up because you think a flag is going to be thrown. You just have to play football and leave the refereeing to the officials."
BIG RETURNS: Cody Hoffman became the sixth player in BYU history to gain 1,000 yards in return yards after returning seven kickoffs for 167 yards, including a 52-yarder in the second quarter.
JD Falslev recorded a 67-yard punt return for a touchdown in the third quarter, which was the first punt return for a TD by a BYU player since 2006, when McKay Jacobson accomplished the feat.
FLAG BEARERS: Former BYU defensive lineman Vic So'oto, who is a rookie with the Green Bay Packers, carried out the alumni flag. Jacobson carried out the team flag and sophomore wide receiver Spencer Hadley carried out the special teams flag.
EXTRA POINTS: Announced attendance was 50,094. … The roof of the Cowboys Stadium dome was open for Friday's game. … TCU now leads the all-time series with BYU, 6-5. The Frogs have won four consecutive games against the Cougars. … TCU has won 33 of their last 36 games and are 45-5 in their last 50 contests.