Turner took the inbounds pass, dribbled upcourt and pulled up barely past halfcourt. The Big Ten player of the year left his arm in the air after the release, confident the long shot would fall.
His attempt was so close to the buzzer that the play was reviewed. When officials signaled the shot was good, the red-clad section of the crowd erupted.
Turner finished with 18 points and eight assists for the Buckeyes (25-7), who advanced to play the winner between Illinois and No. 13 Wisconsin.
Michigan's Manny Harris hit a jumper from 11 feet with 2.2 seconds left to give Michigan a 68-66 lead. Harris led the Wolverines (15-17) with 26 points.
Turner shot only 2 for 9 in the second half after going 4 for 6 in the first 20 minutes, but he showed no hesitation in taking — and making — the biggest shot of the game.
David Lighty and William Buford each scored 15 points for Ohio State. Stu Douglass and DeShawn Sims each had 16 points for Michigan.
The Buckeyes led 39-29 early in the second half before back-to-back 3-pointers by Douglass chopped the Buckeyes' lead to 39-35.
Another 3 by Douglass trimmed Ohio State's lead to 42-38, but Ohio State responded with a 9-0 run. A 3-pointer by Turner capped the spurt midway through the second half.
Michigan surged again, and a 3-pointer by Harris while fading away from beyond the key cut Ohio State's lead to 59-57, leading to frantic final few minutes.
Back-to-back dunks early gave Michigan a 14-8 lead, and a 3-pointer by Douglass extended the Wolverines' advantage to 19-10.
Turner was content to defer to teammates early on, getting three assists and attempting just two field goals in the first 12 minutes.
The Buckeyes rallied and took the lead on a three-point play by Jon Diebler, closing the half on a 25-6 run. Back-to-back 3-pointers by Turner and Buford gave Ohio State a 35-25 lead at the break. The Buckeyes shot 56 percent from the field and scored 17 points off nine Michigan turnovers in the first 20 minutes.