CJ Walker had 10 points and seven assists for the Buckeyes.
Purdue used a 9-0 run to tie the game at 70 on Trevion Williams’ basket with 9.4 seconds left in regulation, but the fourth-seeded Boilermakers wilted in overtime as Ohio State regained its offensive touch following an extended drought late in the second half.
Williams led Purdue with 26 points and 14 rebounds.
Ohio State improved to 4-1 all-time against Purdue in the Big Ten Tournament and drew within four games in the all-time series, which the Boilermakers lead 90-86.
No. 5 seed Ohio State will face No. 1 seed Michigan in the semifinals at 1 p.m. Saturday.
The Wolverines won the only matchup of the regular season 92-87 on Feb. 18.