Deshaun Thomas scored 19 points and Aaron Craft had 14 and six assists as the No. 14 Buckeyes avenged a Jan. 5 loss to Illinois with a 68-55 win on Sunday.
Lenzelle Smith Jr. registered 10 points and six rebounds the Buckeyes (23-7, 13-5 Big Ten), who closed the regular season with five straight wins.
The Buckeyes clinched the No. 2 seed in the upcoming Big Ten Tournament and face the winner of Purdue versus Nebraska on Friday.
"It has been a heck of a stretch coming from where we started after loosing two games in a row, to now," Ohio State coach Thad Matta said. "They have kept practicing, kept the energy and kept their focus. I like where we are right now, winning five straight games is hard to do in college basketball."
Brandon Paul scored 21 points and grabbed five boards for the Fighting Illini (21-11, 8-10), who have lost two straight and three of their last four. D.J. Richardson supplied 10 points in defeat. Illinois will be the No. 8 seed in the conference tournament and will face Minnesota on Thursday.
Illinois didn't go away as the Buckeyes threatened to increase the lead over 10 points in the closing stages of the game.
Paul's jumper with 1:38 to play cut the deficit to 62-55, though Smith responded with a three-point play on the next possession to all but secure the victory.
Thomas opened up the second half scoring Ohio State's first eight points and the Buckeyes continued to hold their edge to 10 points at the midway point.
Tracy Abrams hit a deep jumper with 8:50 to play to bring Illinois within seven, but OSU scored five unanswered to squash any hopes for the upset.
"They're getting contributions from a lot of guys," Illinois coach John Groce said. "I think they're starting to connect a little bit and play together. They're a good basketball team."
Smith's 3-pointer at the 8:25 mark of the first half put Ohio State ahead 18-17, but Tyler Griffey put the visitors back on top, 20-18, with his own triple.
The Buckeyes then capitalized on a 15-4 surge to close out the first half for a 33-24 lead at the break.
"We took care of what we needed to take care of today," Craft added. "The rest, whatever happens, happens. The Big Ten championship is now what we are looking forward to and were going keep our eyes on the prize."
Illinois won the first meeting this season, 75-55 ... It was the first game at Ohio State for Illinois coach John Groce, who spent four years on the OSU staff from 2004-2008 ... Illinois still holds a 104-71 advantage in the all- time series ... The Illini shot 35.2 percent (19-of-54), including just 7- of-25 from downtown ... Thomas, a junior who leads the Big Ten with 19.8 points per game, might have very well played in his last game in Columbus.