Illinois State scored three runs in the bottom of the seventh, the game-winner coming across on a sacrifice fly from Caitlyn Daly that scored Allison Spence to register a 5-4 victory.
The Redbirds scored two runs in the bottom of the second and went scoreless until the final rally. Riley Strandgard had two hits and drove in two runs, while starting pitcher Sarah Finck moved to 22-11 on the year.
IUPUI got three hits from Maggie Armstrong, including two doubles.
Illinois State will play Murray State in the winner’s half of the double-elim bracket on Wednesday, while IUPUI takes on Michigan State in the loser’s half.