Dayton (9-4, 5-3) opened the game on a 9-2 run over the first 3:57 and never trailed in the contest.
Saint Louis tied the game for the first time since the opening tipoff when Perkins hit a jump shot to pull the teams even 53-53 with 4:54 remaining in the second half
The teams traded baskets until the Flyers pulled away on an 8-0 run featuring a layup and 3-point basket from Crutcher.
Crutcher, the Flyers’ leading scorer, scored at least 23 points for the sixth time this season.
Dayton outscored Saint Louis 36-31 in the first half thanks to converting seven of 15 shots from 3-point range.
Saint Louis senior Jordan Goodwin had 11 points and 11 rebounds giving him his eighth double-double in nine games this season to keep him among the nation’s leaders despite Saint Louis missing seven games. Goodwin is one of 10 finalists for the Jerry West Award given to the nation’s best shooting guard.