WACO, Texas — After losing a 38-24 nonconference football game to then-Big 12 heavyweight Baylor three years ago, BYU coach Kalani Sitake sat in an interview room under the East bleachers at McLane Stadium and said the Cougars had a long, long way to go — especially in the trenches — to compete in the league they had been invited to join a few months prior.

Baylor rushed for 303 yards that day, gashing BYU time and again in a physical mismatch.

Saturday, after the Cougars held off favored Baylor 34-28 on a hot, sun-drenched afternoon, Sitake sat in the same room and spoke like a proud father, saying BYU is finding some traction in the Power Four conference after taking its lumps in 2023.

This wasn’t the same caliber of Baylor team than it was in 2021, when it went on to claim the Big 12 championship, but it was a tremendous challenge nevertheless, evidenced by how the Bears played Colorado evenly a week ago on the road in Boulder, only to fall in overtime to a Buffs team that dismantled red-hot UCF on Saturday.

“I like where we are at,” Sitake said, while explaining how depth made the difference on a day when nearly a half-dozen Cougars left the game with injuries. “I am proud of the guys that stepped up. The guys that got banged up were still on the sidelines cheering and leading. They still had a lot of energy and juice. This is a close team. Guys weren’t able to play were in it, creating energy and belief on the sidelines. It was a lot of fun.”

Sitake quickly added that the 5-0 Cougars, who moved up five spots to No. 17 in the Associated Press Top 25 released Sunday, have not arrived. But the view is certainly better, after BYU went 2-7 in its first season in the Big 12 and was picked to finish 13th this year.

“I just like the feeling and the vibe from the team. It is a fun team to coach, and I freaking love these guys, man,” Sitake said. “We are having a lot of fun. And it is crazy, because in that tense moment (at the end of the game), I had guys behind me just having so much fun with it.”

The coach said the feeling took him back to when he played youth and high school football, and the game was all about having fun.

“Hats off and credit to our players for being good examples to me,” he said. “It is awesome.”

So BYU, the only 5-0 team in the Big 12 (Iowa State is 4-0), has emerged as one of the biggest surprises in the country. ESPN’s Football Power Index (FPI) predicted 4.7 wins for BYU when the season started and gave the Cougars a 1% chance of starting 5-0.

Now the FPI is predicting 9.1 wins for BYU. It’s been quite a turnaround, fueled by victories in three games the Cougars were picked to lose — at SMU, vs. Kansas State, and at Baylor.

BYU is the only undefeated team in the nation with three wins vs. P4 opponents.

“It just shows that all the hard work we put in from winter up to now is paying off. We probably didn’t see how it was going to end up, being 5-0 and stuff like that,” said receiver Darius Lassiter, who had a career-high 120 receiving yards. “But we trusted the process (laid out by) our strength staff, nutritionists, everybody, that were pushing us to be better this whole winter. So you just see everything fall into place like they said it would.”

In the eight times BYU has started a season 5-0, the Cougars have beat three power conference teams during the stretch just twice — in 2021 and 2024.

Defense and special teams have led the way, but the offense has also improved, and quarterback Jake Retzlaff has shown he has what it takes to deliver victories at home and on the road. The junior college transfer is now 5-4 as a starter, and validating offensive coordinator Aaron Roderick’s decision to make him the opening-day starter back in August.

“That was a great start (when BYU took a 21-0 lead),” Sitake said. “We are capable of doing all those things. We just gotta keep the momentum going. We don’t have to be perfect, but we have to be efficient as an offense. And our defense, when we start playing together, good things happen.”

One of the remarkable stats coming out of Saturday’s win was that a banged up BYU offensive line (and running backs group) did not allow a sack, after Baylor got eight sacks last week at Colorado. Retzlaff dropped back to pass more than 30 times, and arguably made just one bad decision, a throw across his body that was picked off by Corey Jordan Jr. Sitake thought BYU receiver Keelan Marion was held on the play, keeping him from contesting for the catch.

Retzlaff said the adversity was “super beneficial” because it taught the Cougars a little more about themselves.

“We learned our defense is really good, and we learned our offense can start really fast. So, yeah, we just gotta get to the film and figure out what we gotta do better,” he said. “Executing late in the game is obviously on the tops of our minds. But yeah, I was glad our defense was able to execute late in the game and get us the win.”

The Cougars have the first of two byes during the 2024 season this week, then will host Arizona on Oct. 12 at LaVell Edwards Stadium. The Wildcats improved to 3-1 with a 23-10 win over No. 10 Utah late Saturday night and will host Texas Tech this weekend.

“It is going to be nice to not have a game and heal up. Five games straight you get a little banged up,” Retzlaff said. “So the guys can heal up a little bit and just feel more confident in themselves. We will still get back to work. I imagine we will start scout work early on for (Arizona). But yeah, I think it is going to be good for us just to kind of reset a little bit.”

And enjoy a start to the 2024 season that nobody but them saw coming.