Hofstra (10-23) dominated the boards, out-rebounding Delaware 39-28, including 17-8 offensive rebounds.
The Pride took an early lead but Delaware tied it at 32 when Saddler capped a 10-2 run with a pair of free throws. Hofstra surged ahead on back-to-back treys by Zeke Upshaw and led 40-37 at halftime.
Delaware opened the second half with a 13-2 run in which Usher sank two 3s, then led 79-67 after an 8-2 run capped by a Carl Baptiste dunk. Delaware hit seven free throws in the final minute to clinch the win.
Delaware will play fifth-seeded Northeastern in the semifinals on Sunday.