The Blue Hens (15-13, 10-5) made 29 of 42 free throws, including 15 of 21 in the two extra frames. Devon Saddler finished with 31 points for Delaware, 11 of which came from the charity stripe.
"They won the game from the foul line," said a frustrated Flint afterward. "We did a good job, we just didn't come out with it."
Drexel's offense was dreadful out of the gate, going 5 minutes, 32 seconds into the first half without a point before a Frantz Massenat layup broke the drought. The offense was better in the second behind a more aggressive Massenat (17 points, six assists). Teammate Damion Lee finished with 25 points; Derrick Thomas had 19.
"We didn't shoot the ball particularly well," Flint said. "We dig ourselves holes. That is what we've been doing all season."
The Dragons trailed by seven at the half and exhausted a ton of energy (and fouls) coming back. A Lee three-pointer gave Drexel its first lead at 49-48, with 3:41 left. Massenat scored 13 of his 17 points after the first half.
Blue Hens big man Jamelle Hagins owned the glass, snatching 18 rebounds to go with 14 points.
"We were talking that guys have got to start to make tough plays," Flint said. "They were there to be made. We made some of them. We just didn't make enough."