Terpstra scored a career-high 19 points on 7 of 8 shooting and grabbed seven rebounds for the Storm (4-2), who won despite enduring a rash of injuries as of late. Ahrenholtz added 15 points, a season-high for the freshman.
Simpson broke open a close game early in the second half. Leading 41-37 with 14 minutes left, Aherenholtz hit a jumper to spark a 15-6 run. The Storm outscored the Big Blue (3-3) 33-21 to close the game out.
Yip Ypya scored 13 points to lead Millikin.
Simpson will face Robert Morris in Decatur on Saturday.