TAMPA, Fla. - Freshman Brandon Costner already knows what makes a disappointing season bearable at North Carolina State. Try beating North Carolina during the regular season, then knocking off Duke in the Atlantic Coast Conference tournament.

Duke head coach Mike Krzyzewski walks off the court after a 85-80 loss to North Carolina State during a first round game of the Men's Atlantic Coast Conference basketball tournament in Tampa, Fla., Thursday, March 8, 2007. (AP Photo/David J. Phillip)

Costner helped the 10th-seeded Wolfpack (16-14) accomplish that Thursday night, scoring a career-high 30 points and grabbing seven rebounds to help end No. 21 Duke's reign as tourney champions 85-80 in overtime.

"As you all know, the rivalries are great on Tobacco Road, and nothing will make our fans and us happier than to beat Carolina and Duke," Costner said. "To succeed in beating them this year is a great accomplishment."

Engin Atsur scored all 21 of his points after halftime to help avenge a 23-point regular season loss to the Blue Devils (22-10), who had won seven of the previous eight ACC tournament titles, including the past two.

But this time, Duke entered the league's signature event as the seventh seed, its lowest since 1995.

"At this point, we've got nothing to lose. We just want to finish our season strong," said Atsur, who didn't play in the regular-season game against Duke because of a hamstring injury. "We just don't want to finish our season as quick as losing in the first game of the tournament. I think we were mentally stronger than ever and we want to keep doing this."

The Wolfpack advanced to Friday's quarterfinals against No. 2 seed Virginia.

Greg Paulus led Duke with 18 points and Josh McRoberts and DeMarcus Nelson both scored 17. The Blue Devils fell behind 73-70 on Costner's three-point play in the opening minute of overtime and never fully recovered.

"It really hurts a lot because I've been here two years and we've won it," said Nelson, who fouled out late in overtime. "Not being able to have that opportunity this year really hurts. But we have to move on from this and make this a growing opportunity for our team."

Duke played without freshman Gerald Henderson, who served a mandatory one-game suspension for a flagrant foul that broke Tyler Hansbrough's nose during the closing seconds of a loss to North Carolina last Sunday.

The loss was the third straight for the Blue Devils.

"I don't know if our team's gotten tired, gotten worn down," Duke coach Mike Krzyzewski said. "I know they're still working hard, but that can happen at the end of the year. We've tried to take care of that over the last couple of days, but what we attempted to do obviously didn't translate into us doing a better job."

North Carolina State rallied from a 60-54 deficit in regulation and had four shots to win in the final 10 seconds. But Costner misfired on a short jumper in the lane, then Atsur and Courtney Fells missed 3-pointers before Atsur's desperation tip flew over the rim at the buzzer.

Costner got the Wolfpack off to a quick start in the extra period, and North Carolina State led 82-76 after Atsur, who was scoreless in the first half on 0-for-4 shooting, made a pair of free throws with 43.4 seconds left.

Martynas Pocius converted a 3-point play to give Duke hope, but the closest the Blue Devils got after that was 83-80. Costner made two free throws to close out the third straight upset in the opening round of the tournament.

This was a rare first-day appearance for Duke, which entered with its lowest seeding since a ninth-place finish 12 years ago. Thursday night's loss stopped a six-game winning streak in the ACC tournament, however the Blue Devils still have won 23 of their last 25 in the league's showcase event.

Henderson, who has said he was not trying to hurt Hansbrough, watched from the stands at the St. Pete Times Forum. Although the 6-foot-8 freshman averages only 6.8 points, he was most effective as a scorer in his past two games, with 15 against Maryland and a career-high 16 against North Carolina.

"He's a very important piece to their team," North Carolina State coach Sidney Lowe said. "He gives them the athleticism, he gives them rebounding, he gives them another guy that can score the ball and defend. Anytime you miss a player like that, it's going to affect your ballclub."

Duke led 34-29 at the half, with Pocius and Jon Scheyer going 5-for-5 on 3-pointers and combining for 19 points. The Blue Devils took charge with an 11-0 spurt, but the Wolfpack refused to go away.

Atsur led North Carolina State's comeback, almost single-handedly keeping the Wolfpack in the game until Costner, who had 16 in the first half, and Ben McCauley asserted themselves inside.

Atsur made four 3-pointers. Costner sank 10 of 17 shots, and McCauley was 7-for-8 and finished with 15 points.

Duke made 6 of 11 3-pointers in the opening half, but was just 3-for-12 from behind the arc after that.

Pocius and Scheyer finished with 14 points apiece.

"The effort of the N.C. State kids was terrific," Krzyzewski said. "Costner was extremely difficult to stop and Atsur's ability to have a calming influence on his team ? no matter what amount of pressure we put on him ? was good. ... Big-time kids, not just big-time players, they do those things."