CHARLOTTE, N.C. -- It was midday Sunday and Phil Snow was the only coach at Bank of America Stadium. The Carolina Panthers defensive coordinator had been there since 7 a.m., two hours later than he had arrived on Saturday, to break down film of the Dallas Cowboys while the team enjoyed a weekend off after a Thursday night game.

There was some concern in Snow’s voice. It was the day before he learned the Panthers (3-0) would trade for Jacksonville cornerback CJ Henderson to replace first-round pick Jaycee Horn, who would go on injured reserve because of a broken foot.

That added to his urgency of preparing for a Cowboys offense ranked fifth in the NFL, averaging 416 yards a game.

This is the life of the 65-year-old architect of the NFL’s top-ranked defense.

“Well, it’s football season, so I’ve got to keep up,’’ Snow said.

Snow does more than keep up. He excels in the only way he knows how, by working twice as hard as most half his age.

To understand such mental fortitude, look no further than a pushup challenge between Snow and 32-year-old offensive coordinator Joe Brady during a hot afternoon before the season.

Coach Matt Rhule likes these challenges because he wants competition at every level, including the staff. What Rhule may not have realized was Snow basically gave up pushups five years ago after hurting his neck.

“But I wasn’t going to back down,’’ said Snow, the second-oldest defensive coordinator in the league behind Atlanta’s Dean Pees, who's 72.

He didn’t back down. He didn’t lose, either.

“The elder statesman won,’’ Rhule said.

Quarterback Sam Darnold called it “old man strength,’’ but Snow’s not old in the eyes of his players. They see the same determination and fight in him that they see in themselves.

“Coach Snow’s young,’’ cornerback Donte Jackson said. “He fits right in with this group. A lot of personality. Yeah, he definitely matches the character of this defense.

“He’s the right lead man.’’

‘Is that coffee pot broken?’

Rhule, 46, first met Snow in 2001. He was a graduate assistant looking for a job as a defensive line assistant at UCLA, where Snow was the defensive coordinator.

“He used to yell for me, ‘Is that coffee pot broken?’’’ Rhule recalled. “I had to go check and make sure he had a cup of coffee.’’

Rhule thought Snow was the best coach he’d ever met.

“He is a special, special man,’’ Rhule said. “I’ve never coached a game without him as my defensive coordinator.’’

Rhule and Snow have been together since 2013, when Rhule got his first head coaching job at Temple. They moved to Baylor in 2017 and then to Carolina in 2020.

While Rhule is the boss, it’s more like a partnership.

“He gives me sh-- sometimes, tells me, ‘Oh, I’m the head coach,’ ’’ Snow said. “I say, ‘Yeah, Matt, I know that.’ ’’

Snow arrived at Carolina under the radar. Most of the attention went to Brady, then a 30-year-old riser who’d just helped LSU win the national championship.

But Snow has stolen the spotlight with a defense that leads almost every statistical category, including sacks with 14. Carolina’s 573 yards allowed is the lowest allowed by any team with a 3-0 start since the 1992 Philadelphia Eagles with Reggie White, according to ESPN Stats and Information.

Snow has done this with players whose average age is 25.6, tied for the fifth-youngest defense in the NFL.

“I love him as a coach,’’ 23-year-old edge-rusher Brian Burns said. “He brings a very versatile defense. He lets the guys play. Like he keeps it simple for us. He puts us in position to make plays.’’

Snow's defensive schemes even feature 'weird fronts'

Snow won at Temple with a 4-3 scheme that ranked fourth nationally in scoring defense in 2014. He switched to a 3-3 stack at Baylor, and by 2019 had the top defense in the Big 12.

Last season at Carolina, he switched from a base 4-3 to a 3-3-5 that allowed an undermanned group to get more pressure on the quarterback.

In Week 15, Carolina held the Green Bay Packers' Aaron Rodgers to a season-low 143 passing yards and had the 2020 NFL MVP referenced Snow’s schemes as “weird fronts."

This season, with new pieces such as edge-rusher Haason Reddick and defensive lineman Morgan Fox, the Panthers have played 59.2% of their snaps in nickel, 33% in their base 4-3, 28% in dime and 1% in heavy (three defensive backs).

While slightly under the league average (60.8%) in nickel, the Panthers have allowed an NFL-low 3.2 yards per play in that scheme. New Orleans is next closest at 4.3.

“Phil does an amazing job of taking stock of what he has personnel-wise, what they do well,’’ Rhule said. “And he’s going to do relentless work.’’

'Old-man strong'

Snow lives in a condominium about two miles from the stadium. He has a couch in his office, something he didn’t have at Temple, so he occasionally sleeps there.

That happened after the Panthers beat the New Orleans Saints in Week 2 and had a short turnaround for the Thursday night tilt with the Houston Texans. Rhule had to remind Snow on Monday to leave so he could return to take his weekly test for COVID-19.

Then it was back to work on a plan that would hold the Texans to 193 total yards.

Snow did sneak in a workout. That was instilled in him in 2005 as a linebackers coach under then-Detroit Lions defensive coordinator Dick Jauron.

“One day Dick said, ‘C’mon, Phil. Let’s go work out,’’’ Snow recalled. “I said, ‘Coach, I don’t have time.’ He said, ‘Listen, you’re going to have time with me every day.’

“If you’re not organized enough to take an hour every day, something’s wrong.’’

Snow’s workout these days includes a “bear crawl’’ where he goes sideways across the field on all fours. It’s not easy. His players and other coaches take notice.

“Phil’s strong,’’ Brady said. “He’s not just old-man strong.’’

Carolina’s defense is a reflection.