Nolan Smith scored a game-high 20 points as No. 5 Duke used a 21-2 first-half run to rout visiting North Carolina State 76-52 on Saturday.

Mason Plumlee had 16 points and 12 rebounds for the ACC-leading Blue Devils (21-2, 8-1 ACC), who improved to 6-1 in their past seven games and moved one game ahead of second-place North Carolina.

Richard Howell scored 18 points for N.C. State (12-11, 2-7 ACC), which lost for the seventh time in eight games.

Duke, which plays host to North Carolina on Wednesday, capped its season sweep of N.C. State with a dominating first half. The Blue Devils shot 64.5 percent from the field in the opening 20 minutes - including 6 of 10 3-pointers - and forced 12 turnovers in building a 53-24 halftime advantage.

Leading 10-8, the Blue Devils scored the next 14 points in a surge that eventually staked them to a 31-10 advantage on Seth Curry’s jumper with 8:27 left.

Smith scored seven of his 18 first-half points during the run, and Plumlee added six. Duke closed the first half on with a 13-3 spurt.

Kyle Singler added 14 points for Duke.

N.C. State next plays Feb. 13 at Wake Forest.