Malcolm Delaney scored 21 points, including two key free throws with 36.6 seconds left, and Virginia Tech kept North Carolina in its worst tailspin since a five-game losing streak in 2002-03 with a 74-70 victory Thursday night.
Delaney's free throws doubled the lead to 71-67 for the Hokies (17-4, 4-3 Atlantic Coast Conference), and the only basket the Tar Heels could manage thereafter came at the buzzer, sealing the fifth loss in six games for last year's national champions.
Dorenzo Hudson added 17 points and Allen had 14 for Virginia Tech.
The Tar Heels were led by Ed Davis with 15 points and John Henson with 14.
North Carolina (13-9, 2-5) appeared to have pulled within one when Will Graves' 3-point try with just under 20 seconds left went halfway down and then rolled out. Jeff Allen rebounded for Virginia Tech, was fouled and made a free throw for a five-point lead.
