The win ended a four-game losing streak for the Bison (4-9), while the Blue Hens had their two-game win streak snapped.
Andrews nailed a 3-pointer with 13 seconds left in regulation to tie the game at 70, sending it into the extra frame.
After Josh Brinkley converted 1 of 2 free throws to give the Blue Hens (5-5) a 71-70 advantage, Thompson and Andrews took over. Delaware reeled off a 9-2 run to take a 79-73 lead at the 2:35 mark.
The Bison closed out the game by hitting on 8 of 9 free throws to seal it, outscoring the Blue Hens 18-13 in the extra frame.
Jarvis Threatt led Delaware with 17 points.