IOWA CITY - Iowa couldn't hit a 3 or get the defensive stops it needed, and stars Devyn Marble and Aaron White were outplayed by Ohio State's Aaron Craft.
The Hawkeyes have now lost back-to-back home games - and their hopes for a Big Ten title are slipping away.
Craft had 17 points with six assists and six steals to help Ohio State upset 17th-ranked Iowa 76-69 on Tuesday night for its third win in four games.
Mike Gesell had 16 points for lead Iowa (17-6, 6-4), which shot just 3 of 20 from 3-point range.
The Hawkeyes fell 2 games behind idle Michigan and Michigan State in the league standings with eight to play. Iowa hosts the Wolverines at home on Saturday in a virtual must-win to stay in the Big Ten race.
"We played hard tonight. We didn't play well. We never really got in sync. We got behind. We weren't in sync defensively. We made more mistakes than we normally make. We just have to learn from it and get ready for Saturday," Iowa coach Fran McCaffery
LaQuinton Ross added 13 points for the Buckeyes (18-5, 5-5 Big Ten), who moved back to .500 in the league after starting a surprising 2-4.
Craft's first points of the second half came on a three-point play that put Ohio State ahead 66-59 with 1:17 left. That sealed back-to-back road wins for the surging Buckeyes, who beat Wisconsin 59-58 on Saturday.
The Hawkeyes clearly wanted to attack Ohio State from the perimeter. But they missed all but one of their first 14 3s, and the Buckeyes were able to manage a slim lead for most of the second half.
Gabe Olaseni, who had been Iowa's best player for nearly 30 minutes, was called for a flagrant foul on Amir Williams with 8:50 left. Williams, Ross and Shannon Scott all followed with layups that made it 58-49 Ohio State with 6:17 left.
Iowa rallied within four before Williams threw down a dunk off an inbounds pass with just two seconds left on the shot clock. Sam Thompson then buried a 3 for a 63-54 lead with 3:56 to go.
"It was a big play. We cut it to four. I thought (center) Adam (Woodbury) could really disrupt the pass," McCaffery said of Williams' big dunk.
Williams and Lenzelle Smith Jr. each had 12 points for Ohio State, which won despite a 38-25 deficit on the boards. It certainly helped that Iowa was just 12 of 19 from the free throw line.
Olaseni had 14 points, six rebounds and a pair of blocks off the bench.
Iowa soundly defeated Ohio State in their first meeting, rallying from nine down to win 84-74 in Columbus.
At the time it seemed like a breakthrough road win for the Hawkeyes - a sign the program had truly arrived under coach Fran McCaffery.
But the Buckeyes unexpectedly kept losing, dropping three of their next four to fall from No. 3 to out of this week's Top 25 poll.
It was Iowa that looked like the unranked early though. The Hawkeyes missed their first nine 3s and fell behind by as much as 26-17 - until a play more suited for the football field gave them the lead at halftime.
Marble and Gesell trapped Craft near half court. Marble stripped the ball and hiked it under his legs to Gesell, who then chucked the ball like a post pattern to a waiting Aaron White for a slam dunk.
That would prove to be a rare miscue from Craft - and plays like that were few and far between for the Hawkeyes.
"We got good looks. We got the ball inside. We got 15 offensive rebounds, so I think our effort was good there," McCaffery said. "We were looking for different combinations. We had a couple that worked, a couple that didn't. But I thought the guys fought hard."