Mack is back, but I’m not sure we can say the Tar Heels are — because they may never have been in this position before.

A quarterback who was in high school a year ago. Linebackers who had never played linebacker. Others who had never been in a college game. A new coaching staff that was put together quickly by Brown that had been working and practicing and meeting and teaching. But this was their first game trying to do it all in real time.

“These are the mistakes,” Brown said, as he walked into his post-game press conference with a marked-up sheet of glossy card stock. “It’s not all of them. I ran out of room.”

This wasn’t a team playing a bad first half and coming back to play better in the second. This was a team used to playing bad when it counted, losing games in the fourth quarter like it was their cursed tradition.

Down 20-9 with the ball at its own 2-yard line, what was Tar Heel Nation to think but, “Here we go again.” South Carolina coach Will Muschamp, a former Mack Brown assistant at Texas, acknowledged afterward that “the game was in hand.”

Then, almost all of a sudden, almost everything changed. Like it was almost magic.

Two 90-plus yard drives for their first touchdowns of the season and 15 unanswered fourth-quarter points later, the unheralded football Carolina had completely taken over the day at Bank of America Stadium, stunning the garnet-clad fans who came to town knowing they would win.

How many of you watching in person or on TV said to yourself or someone else during the second half when you finally realized it, “Our guys are playing really good football out there?” That’s how swiftly everything seemed to come together.

It was as if Brown — despite all the penalties, missed tackles, fumble and blocked field goal, and other screw-ups in the first half of a typical opening game — managed to not only change the course of action on the field but also change the culture.

How did he really do that amidst all the tumult of being back on the sideline wearing a head set for the first time in five years?

“They believed,” he said, “in what we were telling them.”

With a sharper and shorter training regimen he developed in his later years at Texas and tweaked by watching other coaches prepare their teams during his time away with ESPN, Brown gave his players the stamina to not only hang in a game that looked like it was slipping sway, but come back and win the dad-gum thing.

At the end, this group of kids from future NFL star Myles Wolfolk to true freshman Sam Howell, looked in control while more experienced South Carolina playing for a fourth-year coach looked completely gassed and bewildered by an opponent that had sprung to life with a vengeance. With that 15-for-24 passing performance, 18 year-old quarterback Howell returned to Chapel Hill as the new big man on campus and should be prepared for standing ovations once classes resume Tuesday.

The Tar Heels not only won by 24-20, they owned all the other numbers – first downs, rushing yards, passing yards, time of possession – that mattered the most. Howell, making the jump from a nearby high school field to an NFL stadium, was coached cautiously in the first half, and two trips into the red zone netted only chip shot field goals.

“We were vey conservative with Sam Howell around the goal line early,” Brown said. “We felt like at halftime, he’s the quarterback, we just had to turn him loose, let him go. And he played a tremendous second half.”

I’ll say, completing eight for 13 passes — including two long touch jobs to sophomore Dyami Brown and junior Beau Corrales, who made acrobatic catches in opposite corners of the end zone. Meanwhile, South Carolina’s three-year starter Jake Bentley was being chased around downtown Charlotte by a defense that got fresher and more in sync as the steamy afternoon finally cooled off.

Like weekend golfers having a stretch of good holes and getting into a zone, they all came together and were flying around and having fun, executing like the coaches told them they could if they only believed.  Brown and has new staff had been reminding them, harping on them, all training camp that they could win all the fourth quarters they got used to losing the last two years. And that yesterday’s gone.

Oh, there were still some mistakes and anxious moments at the end for this amalgam of players and new coaching staff. Holding onto their first and only lead of the game, they allowed a short punt to be returned into the danger zone before Wolfolk’s second interception as he read Bentley beautifully and cut across the receiver’s path.

Then with the Gamecocks out of timeouts, the Heels mismanaged the clock to give the ‘Cocks one more Hail Mary chance with 10 seconds left as an anxious light blue fanbase stopped celebrating and held its collective breath. Could their team let another one slip away?

But linebackers Chazz Surratt, the former quarterback, and Tomon Fox, his lesser-known fellow junior, threw Bentley to the turf as the clock finally ran out.

“We obviously need some work on our victory formation and how to use up all the time,” Brown said. “Maybe we never expected to be in that position.”

Those expectations, after what improbably happened to start the season, will be much harder to manage moving forward. Yesterday’s gone and tomorrow’s here, and it’s spelled M-I-A-M-I.