Virginia forward Akil Mitchell hadn’t paid much attention to the NCAA tournament bracket after Selection Sunday, so he had no idea where Tennessee ended up. Until Thursday.

As he walked down the hallway here at PNC Arena, Mitchell did a double-take when he saw those familiar orange-and-white warmups. Because he’ll never forget that one December night in Knoxville, Tenn.

“I wanted to stop and say, ‘Thank you,’ ” Mitchell said.

The Cavaliers will begin the NCAA tournament as a No. 1 seed for the first time in 31 years Friday when they face No. 16 Coastal Carolina in an East Region first-round matchup. An already historic campaign — Virginia had never won the ACC regular season and tournament titles in the same year before this season — could become even more memorable if the Cavaliers (28-6) win their first-round game for the first time since 2007 and then advance past the tournament’s first weekend for the first time since 1995.

But this run never would have happened without several key moments in which the Cavaliers were alternately tested and rewarded. And the journey began in earnest in the locker room at Tennessee on Dec. 30, when a season that began with high expectations — Virginia was ranked in the Associated Press preseason poll for the first time in a decade — teetered toward mediocrity.

The Cavaliers had just suffered a humiliating 87-52 loss to the Volunteers that left them with a 9-4 record in nonconference play. Mitchell and fellow senior captain Joe Harris led a blunt postgame discussion “about how we’re not as talented as we might have thought we were,” Harris said.

More than anything, leading scorer Malcolm Brogdon added, “a couple of us had agendas, and after that we got rid of those agendas.”

Over the next five days, with Virginia’s student body still on winter break and nobody to hang out with besides themselves, the Cavaliers bonded over meals together every day. In a story that has now become famous since Virginia recovered, Harris even drove to Coach Tony Bennett’s home on New Year’s Eve to talk about what had gone wrong.

“There wasn’t any huge meetings. We didn’t kick the coaches out of a practice. Nothing like a movie or anything like that,” Mitchell said.

The Cavaliers didn’t see the fruits of those angst-ridden moments until Jan. 4, when they opened ACC play at Florida State and watched Harris go down with a concussion three minutes into the contest.

Bennett, on the recommendation of assistant coach Ron Sanchez, had changed the offense back to what the Cavaliers used two years ago with former star Mike Scott. He also reinserted freshman point guard London Perrantes to the starting lineup, shortened his rotation to better define roles and forced Virginia to rediscover its defensive identity.

It had been “a feeling-out process,” assistant coach Jason Williford said, because Bennett never had so much depth at his disposal before.

“We had a lot of pieces. . . . Just trying to find the right mix,” Bennett said Thursday when asked about his biggest challenge this year.

But even though Perrantes scored a career-high 14 points and Virginia emerged with a 62-50 victory over the Seminoles, it was Brogdon who got the biggest boost. The redshirt sophomore, who missed all of last season with a foot injury, didn’t need to be the team’s primary ballhandler anymore. Until then, the Cavaliers were on pace to commit more turnovers than any other Bennett-led team.

“I did some things in the game that made me feel like my old self before I got injured,” said Brogdon, the only player in the ACC to score in double figures in every conference game this year.

Blowout wins over Wake Forest and North Carolina State followed before the Cavaliers traveled to Cameron Indoor Stadium to face Duke on Jan. 13. Brogdon was again front and center, almost single-handedly erasing an 11-point deficit to give Virginia the lead over the final four minutes of regulation.

A three-pointer by Duke’s Rasheed Sulaimon that bounced off the rim and through the net ultimately gave the Blue Devils a 69-65 victory, but the Cavaliers came out more confident than when they entered.

“If we can do that here, we can do it with anybody,” Williford said.

From there, Virginia reeled off 13 straight wins, including a 75-56 win over Syracuse that gave the program its first outright ACC regular season title in 33 years. But a 48-45 win at Pittsburgh on Super Bowl Sunday might have been more crucial in the long term.

Over the years under Bennett — and at Duke just a few weeks earlier — the Cavaliers had found themselves on the wrong end of several close games. This time, Brogdon hit a game-winning three-pointer and a weight had been lifted.

“That’s the hardest game I think we’ve played all season,” Brogdon said.

Virginia eventually climbed to No. 5 in the national polls entering its regular-season finale at Maryland. That the Cavaliers had little to gain was evident during a 75-69 setback in College Park. They didn’t play poorly, Bennett said, but the desire that was evident over the past two months had disappeared.

It proved to be another reminder of that night in Knoxville, when Virginia realized how fragile its success could be. The Cavaliers responded by winning the ACC tournament, and with a memorable season on the line in every game from here on out, they don’t want to forget the lessons learned along the way.

“That beating definitely helped us. I’ll say it until my senior year,” Perrantes said. “That Tennessee game changed my career. . . . If we would’ve lost by five, it wouldn’t have been that big of a change.”