CHAPEL HILL — Inside the Smith Center, fans started to chant “N-I-T” at Duke.

Outside over on Franklin Street, hundreds were celebrating Carolina’s 91-73 triumph and a season sweep of the series in college basketball’s most storied rivalry. The Tar Heels and Blue Devils met as unranked teams again — first time consecutively since 1955 — but it mattered little for the intensity and bravado that comes with being two of the nation’s most elite programs.

“The enthusiasm of Senior Day, the enthusiasm of the crowd at the Smith Center, the enthusiasm of what you’re playing for this time of year, that led to us playing pretty well,” North Carolina coach Roy Williams said.

Armando Bacot, Kerwin Walton and Caleb Love scored 18 points each for Carolina. The Tar Heels started junior Leaky Black with seniors Garrison Brooks, Andrew Platek, Walker Miller and K.J. Smith.

“That game is always — no matter what the records are, it’s always going to be a sight to see,” Brooks said.

The Tar Heels never trailed, led by 20 early and had few troubles. They’ve shot better in both games against Duke than any other foes down the stretch of the season, and the Heels are positioned to be somewhere between No. 7 and No. 11 on a seed line for the NCAA Tournament.

Duke’s streak of 24 straight trips to March Madness, second-longest in the country and dating back to the Mike Krzyzewski back surgery (his first) year of 1994-95, is in jeopardy. The Blue Devils are 11-11, went 9-9 in the league, and would appear to need five wins in as many days in Greensboro next week at the ACC Tournament.

The Blue Devils open Tuesday about 4:30 p.m. against Boston College in a Nos. 10-15 matchup. Their best winning streak this year is four.

“I didn’t have my team prepared the way they did,” Krzyzewski said. “Coming off these two tough losses, the things we did in practice were really good, but they didn’t come into fruition. They didn’t work out. That’s on me. Because they really knocked us back.”

Carolina (16-9, 10-6 ACC), with only one home loss to Marquette this season, is seeded sixth and plays Wednesday’s final game, about 9 p.m., against the Notre Dame-Wake Forest winner.

All of the Big Four teams, in fact, play either Tuesday or Wednesday and need at least four wins for the title.

“When we all play Carolina basketball, we can be a great team,” Bacot said. “It’s just, when is it going to happen? And can we keep it going?”

Mark Williams led Duke with 18 points, D.J. Steward added 16 and Matthew Hurt 14.

“I think now the biggest thing is just to believe in ourselves,” Williams said. “I mean, that’s the biggest thing. Everyone’s going to be doubting us, but at this point, it’s us against everybody.”

Walton hit 4 of 7 from 3-point range and Love had seven assists. Garrison Brooks added 14 points on 6-of-9 shooting for Carolina.

Bacot scored seven consecutive points to start a 22-4 run that made it 26-6 when he capped the spurt with a dunk midway through the first half.

North Carolina made 31 of 56 (55 percent) from the field, shot 44 percent (8 of 18) from 3-point range, and outscored the Blue Devils 21-12 from the free-throw line. Duke was never closer than 13 in the second half.

“I need to help them more confidence-wise and just coaching-wise, so that they can turn this around,” Krzyzewski said. “They have good attitudes. Our practices are good. They’re good kids. But did we play well? No. Did I prepare them well? No. … I didn’t help them enough, and that’s my responsibility. I’m going to do try to do what I can to help them play well on Tuesday, and not look at anything else.”

Carolina went 10-1 at home, including winning all seven against ACC teams. The Tar Heels shot better than 50 percent in both halves of both wins against Duke, and also in home wins over N.C. State and Louisville.