Sophomore forward Bobby Turner gave Grove City the lead for good with 25 seconds left in the second overtime with a dunk. A steal and assist from sophomore guard Ryan Gerber set up Turner's eventual game-winner.
Hiram had two shots to retake the lead but could not convert.
Grove City trailed 76-71 with 1:35 left but closed the game with a 6-0 run. Sophomore guard Shawn Carr started the run with a pair of free throws while senior guard Matt Phillips added a layup.
Carr finished with a game-high 22 points while Gerber had 14. Both also had seven rebounds. Phillips added 10 points and four assists.
Carr hit a three-pointer with 28 seconds left in regulation, tying the game at 64-64. That three capped a 9-1 Grove City run. The Wolverines took a 68-64 lead in the first overtime but Hiram eventually tied the game at 70, forcing a second overtime.
Grove City led 29-25 at the half. Hiram out-rebounded Grove City, 42-37. The Wolverines had just 12 turnovers in 50 minutes of action. It is Grove City's first overtime road win since a 111-101 quadruple-overtime win at Westminster Jan. 26, 2002.
A.J. White led Hiram (1-5) with 21 points on seven three-point goals. Hiram is coached by former Grove City assistant coach Tim Rice.
The Wolverines will compete in the Marietta Shrine Tournament Dec. 29 against Marietta at 8 p.m.