CHAPEL HILL, N.C. -- Duke came away with perhaps one of its most improbable victories against North Carolina on Wednesday, making coach Mike Krzyzewski particularly proud of the Blue Devils' toughness.

With an in-game injury to a starter and foul trouble staring at the No. 20 Blue Devils, they didn't blink in rallying for a 74-73 victory against No. 5 North Carolina at the Smith Center.

"To have that toughness they displayed with that youth is incredible," Krzyzewski said. "We showed a lot of grit and were able to win. We earned a really hard-fought win tonight."

Grayson Allen scored 23 points, including the go-ahead free throws for the game's final points.

North Carolina guard Joel Berry had his shot in the lane blocked by Duke freshman guard Derryck Thornton, ending the Tar Heels' final chance in the closing seconds.

"We didn't get as a good of a shot as I thought we would get," North Carolina coach Roy Williams said. "We didn't get what we wanted. We didn't have very good spacing, very good movement."

Forward Brandon Ingram added 20 points for short-handed Duke, which rarely led in the game.

"We really fought down the stretch," Allen said. "We fought through fatigue."

Forward Brice Johnson's 29 points and 19 rebounds paced North Carolina (21-5, 10-3 ACC), which dropped into a first-place tie with Miami.

Forward Justin Jackson chipped in 13 points for the Tar Heels, who scored only three points in the final 4 1/2 minutes.

"It's tough to swallow because we had a wonderful crowd, a great bunch of kids who really wanted to win," Williams said. "... You've got to make plays."

Guard Luke Kennard had 15 points and center Marshall Plumlee added 11 points for Duke (20-6, 9-4), which has a five-game winning streak.

Johnson had nine of North Carolina's first 11 points of the second half, and he seemed set to take control of the game.

But in the waning minutes, Duke repeatedly turned to Ingram and Allen.

"Brandon and Grayson were just awful hard for us to handle down the stretch," Williams said. "At the end, they just opened the floor and kept driving."

Yet at times the plan went well for the Tar Heels, who were hoping to use their depth to create an advantage.

By the early stages of the second half, Duke was without injured starter Matt Jones (severely sprained ankle), and the fouls started mounting, with Thornton hit with his third foul.

"The guys fought through," Plumlee said. "It took every bit of effort and everyone locked in. ... We were locked into winning and we were able to pull it out."

Plumlee, who shot 5-for-5 from the field in the first half, picked up his third and fourth fouls in a 13-second span, going to the bench with 14:06 left.

Yet Duke was within 62-60 with nine minutes to play.

North Carolina scored the next six points, the last two by Jackson when he rebounded his own miss in transition. But Ingram converted twice for the Blue Devils and Allen's three-point play cut the Tar Heels' lead to 70-69 with 4:17 to go.

Kennard's 3-point shot with 2:36 left gave Duke its first lead of the second half at 72-71.

Forward Kennedy Meeks put the Tar Heels back on front on another of the team's second-chance points. Allen's two free throws with 1:09 left changed the lead again for the final time.

Allen missed a jumper with a chance to extend the lead, setting up North Carolina's failed final possession.

"We didn't do what we needed to do to win the game," Johnson said. "They were more aggressive. It's just heartbreaking."

North Carolina raced to a 46-42 halftime lead, buoyed by 50-percent shooting from the field and 10 offensive rebounds.

"We had a hard time stopping them in the first half," Krzyzewski said. "We scored enough points to stay close."

These teams have two of the highest-rated offenses in the country and that was evident during the first half, though Duke came up empty on its final two possessions of the half.

Johnson racked up 18 first-half points, making 8 of 10 shots from the field. The Tar Heels were credited with 30 first-half points in the paint.

Kennard, coming off the bench, scored seven consecutive Duke points as the Blue Devils took a 20-18 lead.

That helped make up for the loss of Jones, who exited after landing awkwardly as he came down from taking a shot. He was assisted out of the arena and came back on crutches to watch the second half.

North Carolina threatened several times to pull away, but the Blue Devils had efficient stretches of offense. The Tar Heels held the biggest lead of the half by either team at 40-33.

North Carolina had two offensive rebounds in the first minute, giving it more than the entire game Sunday against Pittsburgh.

NOTES: This marked the 141st consecutive meeting when at least one of the teams has been ranked in The Associated Press poll. Of those, 126 games have featured a Top 10 team. ... Duke had won four meetings in a row against the Tar Heels, and 11 of the previous 14 meetings. ... North Carolina was coming off a season-high 59.3-percent shooting from the field Sunday against Pittsburgh. ... Duke G Grayson Allen is in line to become the ninth player in program history to lead the team in scoring and assists in the same season. ... North Carolina completes a three-game homestand Saturday against No. 11 Miami. ... Duke finishes a stretch of four consecutive games against ranked opponents Saturday at Louisville.