R.J. Mahurin had a career-high 14 points off the bench, and Carl Richard and Jordan Printy each finished with 11. Jake Odum added 10 for the Sycamores, whose last win over a ranked team came on their own court against No. 14 Butler on Dec. 12, 2006.
Vanderbilt (6-4) lost its third non-conference game at home this season. The Commodores hadn't played since beating Davidson 87-83 on the road Dec. 7, which put them back into the Top 25.
The 10-day break for finals was so filled with exams that Vanderbilt coach Kevin Stallings had trouble scheduling practices and often didn't have all his players on the court when he did. John Jenkins, the Southeastern Conference's leading scorer last season and averaging a league-best 21.3 points this season, was held to 11.
Looking rusty, Vanderbilt fell behind by 12 early. The Commodores scored only once after Lance Goulbourne's three-point play with 6:32 left, and Jeffery Taylor's layup with 53.2 seconds remaining just wasn't enough.
Taylor finished with 21 points and Brad Tinsley had 12.
The Sycamores led by as many as 12 in the first half and nine in the second half. Vanderbilt rallied to take the lead each time and led by as much as 53-45 with 6:32 left on Goulbourne's three-point play. The Commodores then went cold and shot so poorly late that fans started heading for the exits in the final minute.
Printy hit a 3-pointer, then McWhorter put Indiana State ahead to stay with his free throws. Odum scored four of his 11 points in the final 2:44 to help seal the win.
Indiana State outshot Vanderbilt 43.1 percent (22 of 51) to 38 percent (19 of 50), and the Sycamores were even better from 3-point range. They hit 10 of 21 compared to Vandy's 6 of 22. Jenkins, leading the nation with 3.9 3-pointers per game, was just 1 of 6 beyond the arc.
The Commodores struggled shooting even at the free throw line, hitting only 11 of 18.
With the game tied at 28 at halftime, Indiana State scored 10 of the first 11 points to open the second half and led 38-29 on a fast-break layup by Odum.
Taylor started a 12-0 run with a 3, a pair of free throws, another 3 and then a high-flying dunk off a steal by Tinsley that had fans roaring. Tinsley then scored on a layup for a 41-38 lead with 15:21 left. Vanderbilt grabbed its biggest lead at 53-45 but didn't score again until it was too late.