Delaware's Kyle Anderson stole the ball from Four McGlynn with under a minute left, leading to two free throws by Holden with 23 seconds left. McGlynn banked in a 3-pointer with six seconds left, but Holden capped the scoring with two makes with four seconds left.
Delaware (10-19, 9-9 Colonial Athletic Association) will be the sixth seed in the conference tournament.
The Blue Hens' Marvin King-Davis had 11 points and 10 rebounds for his second double-double in three games. Jeffers had 13 first-half points as Delaware held a 31-30 lead.
Towson will open the CAA tournament against Elon on Friday.