"We were fortunate that we were able to get back and not commit too many turnovers where they had runs," Duke coach Mike Krzyzewski said. "We committed turnovers, but they didn't have runs where they had the numerical advantage."
By keeping the game almost entirely in the halfcourt, the Blue Devils and their vaunted defense simply were too much for North Carolina.
North Carolina squandered a chance to win in the final seconds, never getting a shot off after inbounding with 18 seconds left. David Noel dribbled the ball out of bounds just as the buzzer sounded and the Cameron Crazies raced onto the court, celebrating the Blue Devils' 15th victory in the past 18 games in this Tobacco Road rivalry.
"It seemed like a long time, and I was just hoping that that clock went down before they got a shot off," Nelson said. "We played some great defense, and we made them try to do something that they weren't ready for."
Ewing finished with 15 points and helped the Blue Devils (18-2, 8-2) move into a first-place tie with North Carolina in the Atlantic Coast Conference. Wake Forest trails both by one-half game.
Duke (No. 8 ESPN/USA Today; No. 7 AP) finished 21-of-22 from the free throw line and made 10 3-pointers. All but one of the Blue Devils' baskets in the second half were 3s -- only a layup by Nelson with about 10 minutes left came from inside the arc.
Instead of running with the Tar Heels, Duke held the ball on many possessions, milking time and letting Redick, Nelson or Daniel Ewing drive in the waning seconds of the shot clock. The strategy worked perfectly.
"They slowed us down when they got the job done on offense," North Carolina coach Roy Williams said. "I mean, they spread the floor and controlled the tempo that way. And in their pressure defense, there's no question that bothered us, too."
Sean May had 23 points and 18 rebounds for the Tar Heels (19-3, 8-2), who couldn't overcome their shoddy ball control. Point guard Raymond Felton had eight turnovers and May added five, and the top assist team in Division I finished with only 10, 11 below its average.
They were held to their lowest point total since also scoring 70 in a victory at Indiana in December.
"They're good, they're solid," May said. "They don't run many traps or scrambles, they're just solid man-to-man pressure. They play better D at home just because of the fans the atmosphere they bring. They're almost as solid as you can get."
Felton scored 13 points and freshman Marvin Williams had 12 for North Carolina.
But Nelson was the better first-year player in this one. He had a career-high four steals and came up big offensively when it counted, swishing two 3-pointers in a span of about 90 seconds in the second half to help Duke take a 49-42 lead.
"It was obvious that DeMarcus just played at a level, or even a couple of levels, higher than he's played," Krzyzewski said. "We really needed that. To win a game like this, at times you need something that's different from what you normally do. DeMarcus did that."
Williams helped the Tar Heels rally, powering over Shavlik Randolph for a layup that turned into a three-point play to tie it at 53 midway through the second half. Ewing connected on consecutive 3s, Nelson added four free throws and Redick had another 3-pointer to give the Blue Devils a nine-point lead.
"We were pretty patient on offense," Redick said. "We had a few dumb turnovers, but the main thing for us was just getting back on defense. They only had a few fast-break opportunities, and that's because we hustled back."
Felton scored six quick points to offset two more free throws for Nelson, and May knocked down two at the line to bring the Tar Heels within three. Randolph increased the lead to five with Duke's final points -- again coming on free throws -- and it was 71-66 with less than 2 minutes left.
May worked inside to tip in a miss by McCants, and Williams stuffed a layup by Nelson to set up McCants' layup on the other end that cut the margin to one point. Redick then was forced to launch a shot from about 28 feet with the shot clock winding down, and the Tar Heels took possession with the game on the line.
Felton passed up an open shot to look down low for Williams or May, and he finally passed to Noel. But with time running out, Noel couldn't get off a shot, and Duke survived.
"I should've took it, it was a mistake I made," Felton said. "I was looking for Rashad on the other side of the screen, so I took it back out. He wasn't open, and Sean wasn't open on the slip. So the whole play just got terminated just like that."
McCants, the leading scorer for North Carolina, was only 3-of-13 from the field and had 11 points.