Boutte, who missed a potential game-winner late in regulation, tied it twice in overtime with a jumper and two free throws that made it 69-69. IUPUI ran a double-team, full-court trap and Boutte stole the ball from Jeremie Tyler.
Marcellus Barksdale drained the clock down and threw an errant pass out to Boutte, who saved it from going past the half-court line, cut through two defenders and sank a one-handed floater at the buzzer.
Boutte finished with 16 points, Aaron Brennan added 14 and Mason Archie II had 13 for IUPUI (2-2). Archie converted a three-point play to tie it in regulation.
Sean Sellers led Ball State (1-2) with 22 points and Matt Kamieniecki had 11 with 15 rebounds.