Indiana State trailed Southern Illinois by 17 points after three quarters.
The final quarter saw the Sycamores erupt for 30 points alone, but the deficit was too much to overcome as ISU dropped its 5th straight contest, 70-66.
Wendi Bibbins led the team 16 points and collecting 13 rebounds, her fifth double-double this year.
The Trees are now 12-16 overall, 6-11 in the MoVal.
The regular season finale is on Saturday when ISU hosts Evansville for senior day.
Tip off is at 2pm.