– Things have suddenly gotten a bit tougher for No. 2 Duke now that the Blue Devils are in Atlantic Coast Conference play.

After a series of double-digit victories to start the season, the Blue Devils followed a tougher-than-expected road win against an instate ACC rival by losing for the first time this season, at North Carolina State. Duke trailed at halftime for the first time and by 19 in the second half in Sunday's 87-75 loss to the Wolfpack, a game that coach Mike Krzyzewski said would be a lesson for a team led by freshmen.

"I don't think we were as a tough as we needed to be," he said. "I don't think that means we're bad people or anything. I think you learn through experience how tough you need to be."

Duke had won its first 13 games by at least 10 points before Wednesday's 73-65 victory at Wake Forest, where the Blue Devils faced their first second-half deficit of the season. This time, they just couldn't keep up with a hot-shooting Wolfpack team that played with aggressive confidence.

"We'll definitely look back and be like, 'Man, we've got to dive on the floor, we've got to do the things that make Duke what Duke is.' " sophomore Matt Jones said.

Trevor Lacey scored 21 points and the Wolfpack shot 55 percent in knocking off one of the last three undefeated teams in the country.

The Wolfpack (12-5, 3-1) ran constant double-teams at preseason All-America Jahlil Okafor to slow Duke's big man. N.C. State made 10 of 16 three-pointers and shot 58 percent after the break.

Okafor finished with 23 points and 12 rebounds, but the Blue Devils (14-1, 2-1) shot 37 percent. Quinn Cook scored 18 points for Duke, which missed 20 of 27 3-point tries. Apple Valley's Tyus Jones scored four points, with a team-high four assists.

The Wolfpack built a 72-53 lead — Duke's biggest deficit all season by far ► — then did enough to turn away the Blue Devils' late comeback attempts. Ralston Turner scored 11 of his 16 points after halftime.