BALTIMORE -- Derrick Thomas scored 19 points, including three free throws in the final 1:27, to help Drexel hold off Towson 66-63 on Saturday.
Dartaye Ruffin scored 13 of his 15 points in the second half for the Dragons (20-9, 11-7 Colonial Athletic Association), who reached 20 wins for the first time since 2006-07 and clinched the fifth seed for the CAA tournament.
Drexel will have a rematch with Towson (4-25, 0-18), which has lost 18 consecutive games, in Friday's first round.
Isaiah Philmore hit a jumper to pull Towson to within 63-61 with 1:55 left, but Thomas countered with a free throw.
After Dre Conner made two to cut the lead to 64-63 with 39 seconds left, Thomas hit two more with 17 seconds to play.
Towson's Brian Morris missed a 3-pointer at the buzzer.
Drexel's Daryl McCoy had 13 rebounds.
Josh Brown scored 21 points, and Philmore had 15 and 10 rebounds.