The seniors who led the fifth-ranked Blue Devils to last year's national championship have yet another Atlantic Coast Conference title to savor.
Beating their fiercest rival only made it sweeter, too.
Smith had 20 points and the Blue Devils ended No. 6 North Carolina's run of big comebacks at the ACC tournament, beating the Tar Heels 75-58 in Sunday's final.
Singler added 11 points for the Blue Devils (30-4), who led the entire way for a record 19th tournament title. They won their third straight tournament and their 10th in 13 years, the latest sign of just how seriously they have approached this event over the years.
"I love the ACC. The ACC has made me a better coach," Krzyzewski said. "I just feel that when you are a part of something that's bigger than you and you're in a tournament representing that conference, you should try to be at your best. That's my attitude with it.
"We don't talk about the NCAA tournament or anything like that. We just say we want to win this tournament. You could see how happy we are."
That much was evident when Smith and Singler checked out for the last time with 52.4 seconds left to a standing ovation from Duke fans. North Carolina coach Roy Williams joined the applause from his sideline.
"I said it after we played them over there: they're two marvelous players, and you don't see seniors hang around that much and play," Williams said. "What they did was fantastic."
Now the Blue Devils can focus on the NCAAs again, where they have put themselves in line for a possible No. 1 seed.
Krzyzewski and sophomore Mason Plumlee felt the Blue Devils deserved a No. 1 seed.
"But at the same time, it doesn't matter where we end up," Plumlee said. "One seed, 2 seed, 3 seed, we'll be ready to play."
Only a week ago, North Carolina (26-7) handled Duke with relative ease in a winner-take-all game for the outright regular-season title. This time, in the first finals meeting between the rivals in a decade, second-seeded Duke led by 18 points in the first half and never let the Tar Heels get close to a third straight tournament escape.
North Carolina had rallied from 19 down in the final 10 minutes to beat Miami on a last-play layup in the quarterfinals, then rallied from 14 down to force overtime and beat Clemson in the semifinals. This time, the Tar Heels got no closer than nine after halftime.
Smith was named tournament MVP after overcoming a jammed toe in the quarterfinals against Maryland and finishing with 10 assists, while Singler played better after struggling mightily in the two regular-season meetings. In addition, the supporting cast that pulled a no-show in last week's 81-67 loss backed them up this time.
Seth Curry had 20 in that game and added 11 in this one, including a 3-pointer after the Tar Heels had pulled to within nine. Ryan Kelly added another 3 a few minutes later that helped silence North Carolina's last-gasp push and finished with nine points.
Kelly, Plumlee and Miles Plumlee combined for 24 points on 11-for-16 shooting against North Carolina's powerful front line; they had nine points on 4-for-15 shooting in the loss.
"It was the ultimate team effort," Smith said. "Everybody made big plays. When you do that, there's something inside you that you just have to feel good and we felt that."
Duke shot 62 percent in the first half and 50 percent for the game. The Blue Devils also shut down North Carolina's transition offense behind Smith, who harassed point guard Kendall Marshall so much that Williams yanked the normally steady freshman twice in the first 7 1/2 minutes.
Harrison Barnes struggled to get going a day after scoring a tournament freshman record 40 points, finishing with 16. Tyler Zeller had 14 points while John Henson added 10 points and 18 rebounds, but North Carolina shot 34 percent and never looked like the team that had won 19 of 21 games.
Then again, the Tar Heels never looked like themselves in Greensboro at all.
Henson acknowledged after the Clemson win that the Tar Heels couldn't keep overcoming these bad starts much longer. Yet North Carolina started with the same indifference from the previous two games, while Duke looked more active, more aggressive and just more determined from the opening tip.
The Blue Devils scored on their first four possessions for an 8-0 lead while North Carolina bumbled its way through the opening 2 minutes. That lead would grow to 18 points when Andre Dawkins took a kickout feed from Smith and buried a 3 to make it 40-22 with 1:42 left before halftime.
The Tar Heels didn't make much of a push until the final 7 minutes when Barnes hit a 3-pointer then followed with a jumper that bounced high off the back of the rim before dropping through the net. That brought the Tar Heels to within 63-54 with 5:54 left and had a largely light-blue tinged Greensboro Coliseum crowd into a roar that another improbable rally could be in the works.
But Smith evaded a trap out near halfcourt then found Curry on the left side for a crushing 3 that pushed the margin back to 66-54. Then, after Barnes missed a good look on a transition 3, Smith found Kelly in the right corner for another 3 that made it 69-56 with 4:44 left.
Smith added two free throws then Mason Plumlee threw down a victory-punctuating dunk for a 73-56 lead.
"They were more aggressive," Henson said, "and they had more want-to than us."