Callahan, who scored 20 points, cleaned up a miss by Nate Wolters, who led all scorers with 32. That gave the Jackrabbits (5-3) a 95-93 lead.
A free throw by SDSU’s Brayden Carlson made it 96-93 before Alex Young, who had 28 points for the Jaguars (2-6), missed a 3-pointer with 15 seconds left. Another Carlson free throw sealed the win.
IUPUI took its first lead of the second half, 82-80, on consecutive 3-pointers by Young. A Wolters 3-pointer and two Callahan free throws put SDSU back up by three.
With six seconds left, IUPUI’s Sean Esposito was fouled and made one free throw, but missed his second. Young grabbed the offensive rebound, was fouled and sank both shots to force overtime.