GREENSBORO, N.C. -- Kay Yow left the North Carolina State team to fight cancer. She came back for moments like these.
The Wolfpack (No. 25 ESPN/USA Today; No. 24 AP) spoiled No. 1 Duke's perfect season on Saturday, giving the Hall of Fame coach a second signature post-comeback victory with a 70-65 win over the Blue Devils in the semifinals of the Atlantic Coast Conference tournament.
"This emotion lifts me up," Yow said. "I feel stronger with this. ... We've got to keep going. This is no time to stop."
Ashley Key hit the go-ahead jumper with 1:19 remaining for N.C. State, which has won 10 of 11 since Yow returned from a two-month leave to fight a recurrence of breast cancer.
"I'm not an emotional person, but a couple drips fell today," Key said. "I think it's an amazing win for an amazing coach and an amazing program."
Key's jumper from the left wing made it 66-65. Duke then worked the ball inside to center Alison Bales, who missed a layup.
Sasha Reaves made two free throws with 18 seconds remaining to push the lead to three points, and Abby Waner's potential game-tying 3-pointer from the key failed to hit the rim with about 9 seconds left, and Key hit two free throws with 7 seconds remaining to seal Duke's first loss since last year's title game against Maryland.
"It hurts my heart, but we know that we'll learn from it and we'll get better," Duke coach Gail Goestenkors said. "Definitely better now than later."
Key finished with 21 points for the fourth-seeded Wolfpack (23-8), who reached the ACC finals for the first time since 2001.
As the buzzer sounded, Yow received a hug from assistant Stephanie Glance, and the jubilant Wolfpack players danced and whooped it up at midcourt.
"I just praise the Lord that I can be here and be a part of this this year, that I was able to come back," Yow said. "And I'm so grateful for that."
On the other bench, the Blue Devils could only stare at the celebration in disbelief as reality hit: Their perfect season was no more.
"Our goal was never to go undefeated," Bales said. "With this loss, it will make us work a lot harder that we might have at practice, knowing that we have to go back out there and prove ourselves."
The Wolfpack will play in the final Sunday against No. 4 North Carolina, whichbeat Maryland (No. 5 ESPN/USA Today; No. 6 AP) Saturday in the other semifinal.
N.C. State has already beaten the Tar Heels once before -- a 72-65 upset of then-No. 2 North Carolina on Senior Night when the school renamed the Reynolds Coliseum court after Yow.
A repeat of that performance, and they'll reach even bigger things -- their fifth ACC tournament title and first since 1991.
"We'll just have to go with our same mind-set that we've had," Yow said. "And if we are better on that day, we get it."
Waner and Bales finished with 17 points apiece to lead Duke (30-1).
The Blue Devils were denied their first trip to the ACC title game since 2005, and both the nation's longest winning streak and the best start in school history were spoiled by a fired-up N.C. State team. Duke's loss leaves No. 17 Middle Tennessee's 24-game streak as the nation's best.
Gillian Goring and Khadijah Whittington had 12 points apiece, and Marquetta Dickens added 10 points for the Wolfpack, who earned their first victory over a No. 1 team since Jan. 12, 1978, when they beat Wayland Baptist 98-86.
They did it by frustrating the Blue Devils' two all-conference stars. Bales and point guard Lindsey Harding were a combined 7-of-26 shooting -- with Harding, the league's player of the year, finishing 3-of-13.
"On any given night, [Harding] can go off -- it doesn't matter who's on her," Key said. "I just tried to make it a little more difficult for her."
Early on, Duke seemed on its way to an easy win. The Blue Devils started with a 14-2 run and made 10 of their first 13 shots. But they suddenly went cold at the 8-minute mark, missing their final 11 shots of the half.
Meanwhile, N.C. State used an 11-1 run to make it a one-point game late in the first half. Shayla Fields' jumper in the opening minute of the second half gave N.C. State its first lead at 35-34.
"We built that lead, but we didn't put them away," Goestenkors said. "Once they started to build some momentum, they gained some confidence. We didn't match the early emotion that we had."