Andrea Barbour scored 15 points and Brittany Cook had 14 to lead the Hokies (13-9, 0-7 Atlantic Coast Conference).
The Blue Devils (16-5, 5-1) flashed an offensive firepower in the second half that they'll need against the Tar Heels, who lead the nation in scoring offense. Duke shot 59.5 percent from the floor in the second half.
After closing the first half by going the last 6:08 without a basket, Duke diversified its offense. Most of the Blue Devils' first-half baskets came in the paint.
Duke opened the second half with a 13-6 run. The Blue Devils' shooters warmed up as Smith and Abby Waner hit 3-pointers to help Duke extend its lead to 45-30 with 15:07 left in the game.