Cory Raji's two free throws 1:03 into overtime gave BC a 68-66 lead, but the Hokies scored the next seven points. Thorns pushed Virginia Tech in front for good with a 3 from the left wing and followed with a breakaway layup that made it 73-70. Washington then scored in the lane.
The Eagles closed to 73-70 on Shamari Spears' putback, but Thorns made two free throws that pushed the Hokies ahead 77-71 with just over a minute left.
Virginia Tech led 41-33 at halftime.
The Hokies played without second-leading scorer Jeff Allen, who served the final of his league imposed two-game suspension for inappropriate contact with a referee during last Saturday's game against Georgia Tech.