The three-time Big Ten Player of the Year also holds the NCAA record for 3-pointers with 497.
Sports Today: So much for Ohio's high NCAA tournament hopes
Ohio State led by as many as 10 in the first quarter, but the Chippewas scored the last four points of the stanza to close within 15-9.
CMU hung around despite missing 13 of 16 shots in the first quarter.
Ohio State was 6 for 16 but committed four turnovers, but that was spectacular compared to a disastrous second quarter for the Buckeyes.
The Big Ten champions missed 11 of 13 shots from the field and committed six turnovers against an aggressive CMU defense and while being outscored 25-6.
“First of all, give Central Michigan credit,” Ohio State coach Kevin McGuff said. “They played a great game and they deserved to win. They were outstanding today and they’ve got a great basketball team.
“They were well-prepared and their kids really executed at a high level tonight, but I don’t think we handled the adversity of them making shots or them going on a run. We kind of got out of the things that make us a good basketball team. And when that happened, they really made us pay.”
The Chippewas used a 20-1 run that started late in the first quarter to open up a 25-16.
Mitchell halted that by rattling home a jumper from the elbow with 3:12 on the clock.
She had a chance to make it a three-point game with 2:18 left but missed a free throw.
Then the Buckeyes gave up three consecutive 3-pointers, two wide-open looks for Cassie Breen and one a fadeaway by Presley Hudson off the dribble.
That plunged the Buckeyes into a 34-21 hole from which they never recovered.
Ohio State shot 27.6 percent in the first half and committed 10 turnovers.
Central Michigan made 30.6 percent of its shots, had only five turnovers and enjoyed a 28-20 rebounding advantage.
The Chippewas extended their lead in the third quarter with an out-of-this-world shooting performance.
They made 11 of 16 field goals, including 7 of 8 from 3-point range to extend their lead to 67-46.
The Buckeyes found some offense in the third, but not nearly enough.
Ohio State was still outscored 33-25 in the stanza and never got closer than 13 in the fourth quarter.
“I guess it just felt like everything was going in,” Hudson said of the second half. “We got a lot of open shots and even if we weren’t open we felt like we could make ‘em.”
Hudson led Central Michigan with 28 points while Breen had 22.
Stephanie Mavunga scored 16 points for Ohio State while fellow senior Linnae Harper added 14.
“They did a good job of capitalizing on everything we did wrong,” Mavunga said. “They never let up.”
The Buckeyes had a seven-game winning streak in NCAA tournament games at St. John Arena snapped.
Central Michigan ended up making 14 of 27 from 3-point range and won the battle of the boards 46-35.
Ohio State was knocked out of the NCAA tournament in the second round for the first time since 2015.
The Buckeyes advanced to the Sweet 16 the past two seasons but haven’t been to the Elite Eight since 1993, when they made their only Final Four and lost in the national championship game to Texas Tech.