Daishon Knight contributed 14 points and Reggie Lynch added 12 for Illinois State (13-8, 5-4 Missouri Valley), which shot 44 percent from the floor on 55 attempts and controlled the boards 36-26. Akoon-Purcell sank all eight of his shots from the free throw line and his 20 points tied a career best.
Leading by three at the break, Illinois State opened the second with a 9-2 run capped by Knight's 3-pointer to make it 37-27 with 17:40 to play and held on the rest of the way. Buckets from Missouri State's Chris Kendrix twice cut the gap to seven in the final 2:22.
Camyn Boone led Missouri State (8-13, 2-7) with 13 points and Christian Kirk added 10 as the Bears lost their seventh straight.