1 of 11
Scott G Winterton, Deseret News
BYU's #33 Bryan Kariya drags USU defenders while trying to get more yardage as BYU and Utah State play Friday, Sept. 30, 2011 at Lavell Edwards Stadium.

BYU was headed to certain defeat midway through the second half of its rivalry showdown against Utah State.

Then Riley Nelson happened.

BYU coaches wisely inserted Nelson into the game in place of struggling sophomore Jake Heaps, and Nelson sparked the Cougars to an amazing fourth-quarter comeback over Nelson’s former school.

Nelson engineered a 96-yard drive over the game’s final two minutes in leading BYU to a 27-24 win over the Aggies in wild fashion on ESPN Friday evening.

Here’s how BYU graded:

OFFENSE: The Cougars were heading for an 'F' grade when BYU coaches yanked Heaps midway through the second half. Enter Nelson, who famously transferred from Utah State to BYU after an LDS mission.

Nelson breathed new life into the Cougars, and he amazingly found ways to help BYU overcome a double-digit deficit in the final quarter of play. Nelson isn’t as talented at throwing the football as Heaps, but he plays with courage and gets guys around him to play with courage.

Nelson went 10 of 14 for 144 yard and two TDs, and he capped a 96-yard drive with 11 seconds left by throwing a touchdown pass off a deflection to Marcus Mathews.

Nelson’s performance was a stark, stark contrast to Heaps’. For 2 1/2 quarters, Heaps and the BYU offense staggered before Nelson’s late heroics. GRADE: B.

DEFENSE: BYU’s defense struggled mightily to stop Utah State’s terrific running game, especially in the third quarter, but the Cougars regrouped after that and got stops to give the offense a chance. Leading 21-13 early in the fourth quarter, Utah State had first-and-goal and seemed set to put the game out of reach. BYU’s defense bore down, however, and got a stop. The 'D' was much better the rest of the way, getting stops and setting the stage for Nelson to come from behind against his former school. GRADE: B.

SPECIAL TEAMS: JD Falslev’s decision to let a punt go over his head when he could have fielded it near the 30-yard line meant that BYU started its final offensive drive of the game backed up to its own 4-yard line. It was a crucial mistake, but Nelson and the offense somehow overcame it.

Also, BYU kicker Justin Sorensen, who had made seven consecutive field goals this season, badly missed one from 47 yards, and sent an early kickoff out of bounds. GRADE: C.

COACHING: BYU coaches have built their program around Heaps, so it was a courageous decision to bench him after another lackluster performance. Bronco Mendenhall and Brandon Doman should be praised for having the guts to sit down Heaps and try something else, and they got something else big time from Nelson down the stretch. Once Nelson got in there, Doman seemed extremely comfortable calling plays for him and put BYU in a position to succeed GRADE: B+.

OVERALL: If grading this game over 60 minutes, BYU made lots of mistakes and struggled mightily all over the field, but Nelson’s game-changing entrance sparked BYU to life, and the Cougars came roaring back to tear the hearts out of Utah State. Beating Utah State — after the way the game had gone — is simply huge, and it will help as BYU heads into a much easier portion of its schedule. GRADE: B+.