It did everything except score a touchdown.

BYU’s defense prevented SMU from even scoring a touchdown.

The Cougars were chaos. They were money. They simply led BYU to its second win of the season.

Although defensive coordinator Jay Hill’s heart attack only began a little over a week ago, his BYU defense delivered an emotional and dominant performance in the 18-15 victory over SMU on Friday night in Dallas.

With this win, an impressive battle between two defenses, BYU is now 2-0 on the season, a key step toward bowl eligibility ahead of next week’s trip to Wyoming and the Big 12 Conference that follows.

BYU’s defense prevented SMU, a team that had averaged 53 points during a nine-game home winning streak, from scoring a touchdown. The win extended BYU’s perfect 5-0 record against the Mustangs.

BYU held SMU to zero TDs for the first time in eight years.

Heroes? Put them up, there are many of them.

And as a whole, BYU’s defense bailed out an error-prone offense whose quarterback Jake Retzlaff lost a fumble and threw two interceptions due to ill-advised errors. SMU could have used those errors to decide the game, but it didn’t.

“It was ugly, but it was a win,” Ratzlaff said. “The defense played great.”

Linebackers Jack Kelly (5 tackles, 3 QB hurries), Harrison Taggart (8 tackles, 2 pass breakups, 1 forced fumble), Isaiah Glasker (6 tackles, 1 sack, 1 tackle for loss), Blake Mangelson (1 sack), Marque Collins (interception) and Jakob Robinson (fumble recovery) led the key stat columns, but the Cougar front of John Nelson and Tyler Batty was too much for SMU’s offense.

SMU, favored by double digits, was unable to convert BYU’s three turnovers into points.

SMU had five possessions in BYU territory and managed five field goals. On a late drive, after an interception by Retzlaff to an SMU nose guard, SMU had a first down at BYU’s five in the fourth quarter, but got nothing after Robinson recovered a fumble on a reverse call by the referees.

Collins, who transferred from Weber State, stopped another SMU touchdown drive with a fourth-quarter pick, a spectacular steal from the sideline that broke SMU’s morale at the end.

“We’re just finding our rhythm,” Collins told BYUtv. “Our offense hasn’t played well, but we’re supporting them. They’re going to improve.”

On this play, Collins left the post receiver and dove for a pass to the sideline intended for a back running a wheel route. Collins had been studying this route all week, and when he saw it, he laid it out for SMU quarterback Kevin Jennings.

BYU’s offense disappeared in the second quarter for the second week in a row, a confusing series of three-and-outs in which Retzlaff and the plays couldn’t find any of the Cougars’ talented receivers or tight ends.

It was as if Chase Roberts, Darius Lassiter and Keelan Marion had become invisible as the Cougars attacked the line of scrimmage without making even the slightest attempt to spread the field after running back LJ Martin limped off the field with a sprained left ankle.

BYU’s top-heavy and deep receiver group has to be an important part of the offense, but has been disappointingly ineffective during this phase.

This is where Hill’s defense began.

After BYU led 7-0 and 7-6 and then lost to SMU when the Mustangs led 9-7, BYU’s defenders never let up: They applied pressure with three sacks, made ankle tackles, limited SMU’s Miami transfers to short gains in the backfield and forced field goals instead of touchdowns.

The win, without the offense, paints a different picture of BYU’s season. Many expected the Cougars to struggle to win five games this year after last year’s five-win season.

They were favored by just 14 points against Southern Illinois and won by 28. Against SMU, they were underdogs by 11.5 points but won by three points.

As disappointing as BYU’s offense was that night, totaling 336 yards on 64 plays and three turnovers, Retzlaff threw a razor-sharp 26-yard touchdown pass to tight end Mata’ava Ta’ase and his fourth-quarter speed option pitch of 37 yards to Miles Davis, which set up the game-winning field goal, sealed the victory.

But BYU’s failures on first and second downs were reminiscent of the difficulties of a year ago. BYU’s average starting position was its own 28, while SMU’s average starting drive was the 41.

The offensive personnel must focus on the positions of their playmakers and design better plays to get to those weapons.

BYU ran Retzlaff in the second half, taking advantage of SMU’s very aggressive defensive ends. It was puzzling, however, that the Cougars did not attack SMU with Roberts and Lassiter or JoJo Phillips when the run stalled.

Head coach Kalani Sitake said he was disappointed with the offense, but no one pointed fingers at them. He told KSL Radio he advised the offensive players and coaches not to hang their heads, but to work things out.

“I want Jake to redeem himself. I think he will,” Sitake said.

Bottom line: BYU beat an undefeated ACC team on the road after the Cougars offense allowed three turnovers.

That says volumes about Hill and his defense.