DALLAS – Two things happened that Duke couldn’t afford to have occur.

The dam broke for Duke’s defense and its guard trio struggled, for the second time this month against N.C. State, losing 76-64 to the Wolfpack in the Elite 8 on Sunday at American Airlines Center.

Duke (27-9) gave up 23 points in the first 22 minutes of this game; a 12-2 run by N.C. State around the middle part of the second half is where the game swung from the Blue Devils clinging to a slim lead to N.C. State leading by eight.

N.C. State (26-14) will play Purdue, the Midwest region champ, in the Final Four on Saturday. The Boilermakers on a 2019 Virginia-like revenge tour, having lost as a 1-seed in the first round of last year’s tournament. Zach Edey, the 7-4, fourth-year center who’s about to be named national player of the year for the second straight season, had a career-best 40 points in Purdue’s 72-66 win over Tennessee on Sunday.

The dam broke on Duke’s defense.

N.C. State scored on one of its first three possessions of the second half and to that point, the Wolfpack’s points per possession was at 0.64.

The Wolfpack scored on 12 of the next 14 possessions, during which its ppp was 1.64. That was when the game went from Duke leading 29-23 to N.C. State leading 48-40, prompting a timeout by Jon Scheyer.

The other thing that happened that Duke couldn’t overcome was its guard trio going cold.

Jeremy Roach, Jared McCain and Tyrese Proctor were a combined 13-for-42, with Proctor missing all nine of his shots. Those three were a combined 7-for-28, scoring 23, in Duke’s last loss — which was in the ACC tournament to this N.C. State team that’s won nine straight to reach its first Final Four since 1983, and fourth in program history.

Everything about the game shifted in the first few minutes of the second half, N.C. State finding its offensive touch and Duke’s offense unable to elevate and match the Wolfpack.

McCain scored 32 points and Roach had 13. Kyle Filipowski scored 11 but fouled out with 4:52 left and Duke trailing by 12.

Roach made a mid-range jumper on the first possession of the game and Duke only scored two points, on Mark Mitchell free throws, in its next eight trips down the court.

And then came another instance of McCain needing only one shot to find his rhythm.

The freshman hit a transition 3 on a pass ahead by Proctor. He made five free throws on Duke’s next two possessions. He drilled a 3-pointer a couple of minutes later, and ended the first half with 13 of Duke’s 27 points.

When Duke went cold early, its defense didn’t suffer — as you’ve come to expect during the NCAA tournament. N.C. State shot 9-for-34 in the first half; DJ Burns Jr. had eight points but needed eight shots to get there, and DJ Horne had five points on 2-for-9 shooting, which included a banked-in 3-pointer from a tough angle.

Duke’s halftime lead was 27-21, with the Blue Devils holding N.C. State to a points per possession clip of 0.64.