A season-high crowd of 11,827 showed up to help Ohio State raise awareness for breast cancer research and cheer on the Buckeyes, but the bulk of them went home unhappy after Sarah Schulze's three-pointer that could have tied the game failed to hit anything but the Value City Arena floor with .4 seconds left.
Seventh-ranked Ohio State (26-4, 14-3) had a chance to win the game in regulation when Samantha Prahalis dribbled the length of the floor and threw a desperation shot off the glass no good only to see Schulze nearly win the game with a putback, but her shot hung tantalizingly on the rim before falling away.
After Brittney Thomas, who hit the game-tying jump shot with five seconds left in regulation, made a free throw to start the scoring in overtime, Ohio State scored five in a row and looked to be in the driver's seat.
Jantel Lavender created just enough space for herself to bank in a shot over 6-9 Michigan State center Alyssa DeHaan to give the Buckeyes a 62-61 lead, and Prahalis stretched the advantage to four with a fast-break layup with 2:35 to go.
Then the tables turned dramatically as Michigan State rattled off eight in a row.
Aisha Jefferson banked in a jumper from the left elbow to cap the spurt and put Michigan State ahead 69-65 with 31 seconds left.
Prahalis gave the Buckeyes one last bit of life with a three-pointer with 16.6 seconds to go that cut the lead to one, but after Thomas hit a pair of free throws, Schulze airballed a three-pointer that could have tied it.
Ohio State lost for the first time in 19 home games this season.
That the Buckeyes had any chance to win the game probably came as a surprise to anyone who left the arena or changed the channel midway through the second half.
For the first 30 minutes of the game, Ohio State fans did not have much to cheer about.
The home team trailed 46-33 after a Porsche Poole layup for Michigan State with 9:53 to go, but then the Buckeyes finally started to show some life.
Lavender's layup 14 seconds later started a sequence of 7:21 in which the Buckeyes outscored the Spartans 22-10 and surged to the lead.
With 2:18 to go, Ohio State freshman Amber Stokes made just her second three-pointer of the year to break a 56-all tie and bring the crowd to a nearly deafening din, but the Buckeyes could not hang on.
Jefferson made a contested layup with 1:08 to go then Thomas made her shot in the closing seconds.
In between those buckets, Prahalis had a chance to extend the lead to three but made only 1 of 2 free throws.
"I couldn't close it out," said a visibly frustrated Prahalis, who scored 17 points and logged six assists. "I had a couple times I could have with some free throws and missed them. I went 4 of 11 from the foul line and that's just unacceptable. I think it was three times I could have had that one point and we wouldn't have even had overtime. It's just unacceptable."
Her struggles from the charity stripe came as a surprise after she entered the game having made a school-record 47 consecutive free throws. She was second in the Big Ten at 90.0 percent success in league play but had no explanation for what went wrong against the Spartans.
"I don't really know," the sophomore point guard said. "Some went in and out. Some went off a little bit wrong but I don't know."
Lavender led the Buckeyes with 24 in the post. She also grabbed a game-high 11 rebounds for her 17th double-double of the season. Schulze added nine points and 10 rebounds.
Both Lavender and Prahalis played all 45 minutes of the game, and Lavender made it clear the team's effort overall did not meet her expectations.
"I'm very surprised we lost," said the junior. "We've just got to become a tougher 40-minute team. I'm just shocked. We should have pulled that out. There are little things we could have done to turn the game around so we want to fix those things so that won't happen and we won't get upset."
Thomas scored 19 points to lead the Spartans, who improved to 19-8 overall and 10-6 in the Big Ten while strengthening their NCAA tournament resume.
"I give the Thomas kid a lot of credit," Ohio State head coach Jim Foster said. "She played a very good game, made a lot of clutch shots and did what she had to do. She's essentially their only ball handler, but she got the ball in position and knocked down shots. She played very well."
Michigan State beat a top 10 team for the third time this season.
The attendance figure was nearly double the previous high of the season and represented the second-highest in the 12-year history of women's basketball at Value City Arena. On Feb. 26, 2005, Ohio State beat Penn State 61-59 in front of 17,525.