Tony Durant had 12 points and 11 rebounds and Jonathan Pease added 12 points for the Tigers (12-17, 7-11 Colonial Athletic Association), who had lost six of eight. The Tigers, who got a career-best 13 points from Sean Raboin, finished the regular season 11-4 at home.
Alphonso Dawson led the Blue Hens (13-16, 9-9) with 18 points, Herb Courtney added 17 points and 11 rebounds, and Marc Egerson had 14 points. Delaware, which committed 21 turnovers leading to 26 Towson points, had a two-game winning streak snapped.
The Blue Hens will be the seventh seed in the conference tournament, which begins March 7 in Richmond, Va., while Towson will be seeded ninth.
After Dawson capped a 7-0 run with successive baskets to get Delaware within 43-38 with 17:10 remaining in the game, Towson responded with an 18-2 burst to take a 61-40 lead. The spree began with 3-pointers from Williams and Thornton and ended with a left-wing 3 by Rocky Coleman.
Towson played without leading scorer and rebounder Junior Hairston, who sat out after injuring his back Wednesday at Georgia State.
Thornton scored 10 first-half points, hitting a left-side bank shot and a 3-pointer from the left wing to ignite a 10-0 run that ended the opening 20 minutes and gave the Tigers a 38-29 halftime lead.