Boyle sent the game into OT, then scored eight of his 15 points in the extra period to help the Panthers (10-11, 5-5 Horizon) end the Bulldogs' 15-game conference winning streak at home. Kaylon Williams added 16 points and 12 rebounds.
Shelvin Mack scored 23 points and Matt Howard finished with 18 points and 10 rebounds for Butler (14-7, 6-3), which lost to the same team twice in the regular season for the first time since 2004-05. Khyle Marshall had 14 points and 10 rebounds.
The game went into overtime after Boyle hit two free throws with 25 seconds left in regulation to tie it at 72. Down 76-75, the Panthers took the lead for good on Kyle Kelm's layup with 2:30 remaining.