At the end of a historically wild afternoon, Georgia Tech came face to face with its demons.

The Yellow Jackets, whose season has been defined by shriveling in the clutch and getting overpowered in the fourth quarter, rose up Saturday. In a way they had yet to do through nine games, they extended drives, made tackles and came up with plays in the game’s peak moments. Their prize was a victory in the highest-scoring game in ACC history, an unfathomable 68-50 win over North Carolina that abandoned logic shortly after halftime.

Said A-back Orwin Smith, “With this win today, we believe.”

Tech, which has lost three ACC games this season in which it had held a fourth-quarter lead, has found a reason for faith in quarterback Vad Lee, who drove the Jackets for eight touchdowns and two field goals in 11 consecutive possessions, not counting a half-ending one-play possession, and a defense that buckled for much of the afternoon but came through when it should have been its most spent.

“The kids played their butts off,” coach Paul Johnson said. “They played hard, and they made plays.”

Tech improved to 5-5 overall and 4-3 in the ACC, reaching .500 for the first time since it was 2-2 and headed for its horrendous loss to Middle Tennessee State. Improbably, in a season in which the team has played historically ineffective defense and repeatedly demonstrated a lack of focus and energy, Tech is still in play for a spot in the ACC championship game. With Miami’s loss to Virginia on Saturday, Tech will go to Charlotte, N.C., if the Jackets beat Duke on Saturday at Bobby Dodd Stadium and the Hurricanes lose to the same Blue Devils a week later.

Tech may yet go if Miami decides to self-impose a postseason ban in a proactive response to forthcoming NCAA penalties.

“We’re going in like our head’s on fire because we need this win,” Smith said. “Before the bye week, if someone told me we’d be in this position, I wouldn’t have believed it. This is a great feeling, and we’re going to attack it.”

The 50,000 celebrating homecoming at North Carolina may have witnessed the birth of a star celebrating a homecoming of his own. Lee, from nearby Durham, took over for starter Tevin Washington in the third series of the game and never gave Johnson a reason to return Washington to the game.

Lee escaped pressure in the pocket, legged out runs for clutch third-down conversions and thwarted the Tar Heels in the air. He ran 23 times for 112 yards, including two touchdowns. He was 6-for-10 passing for 169 yards with one touchdown and an interception.

“The kid makes plays,” Johnson said.

His playmaking flair and animated style gave the Jackets a lift on a day when the Tar Heels’ offense, ranked No. 16 in the country in scoring and total yards, never seemed to relent.

“Everybody has confidence in Vad,” outside linebacker Brandon Watts said. “Everybody seems to go up to another level when he’s in there.”

Watts was an author of one of the big plays of the game, stopping Tar Heels punter Tommy Hibbard on an ill-advised fake punt attempt from the UNC 25-yard line. On the next play, A-back Robbie Godhigh took a toss from Lee and turned the corner down the left sideline for a 27-yard touchdown that gave Tech a 51-36 lead with 6:21 remaining in the third quarter.

It was one of three touchdowns by Godhigh, all scored in the third quarter. He also came down with a 32-yard touchdown pass from Lee on a third-and-14 play in which he outleaped a UNC linebacker for the ball.

“Robbie’s the shortest guy in the nation, but he will jump and make a play,” Lee said. “He always makes plays for us.”

Tech turned another takeaway earlier in the third quarter, an interception of a screen pass by defensive end Izaan Cross, into a 35-yard field goal by Chris Tanner, a third-stringer and walk-on who was attempting his first field goal since high school in 2007.

It was no defensive masterpiece. Tech allowed 497 yards of offense, and missed assignments and tackles. It was the fifth game this season in which its opponent scored 40 or more points.

“We talked about at halftime, if we could just get a couple of stops, we thought we could win the game,’ Johnson said.

But the Jackets forced seven stops on the Tar Heels’ high-powered offense, not counting the final one-play possession. Five took place in the second half, and Carolina had outscored the opposition 164-51 in the second half before Saturday.

Said Watts, “We just went in at halftime, made some adjustments, made minor tweaks. We didn’t do anything special. Everybody just did their assignment, did their job, got to the ball, wrapped up, made tackles, made some plays.”