Michigan State had every reason to fold.
The seventh-ranked Spartans were coming off a draining loss to rival Michigan and again were down two starters to surging Iowa - which was hosting its biggest game in years.
Michigan State responded with the toughness it has shown so often under coach Tom Izzo and emerged from Iowa City with a season-defining win.
Keith Appling scored 16 points and the Spartans outlasted No. 15 Iowa 71-69 in overtime Tuesday night, handing the Hawkeyes their first home loss.
"I was concerned coming in whether we could get back up off the can. Not physically, we were going to be beat up. I was worried about mentally," said Izzo, whose team fell to the Wolverines 80-75 on Saturday. "We didn't have time to be tired."
Matt Costello had 11 points and 12 rebounds for the Spartans (19-2, 8-1 Big Ten), who avoided consecutive defeats despite the absence of injured starters Adreian Payne and Branden Dawson.
But it took 5 extra minutes - and an Iowa shooting drought that lasted nearly 15 minutes - to pull it off.
Costello's tip-in with 1:14 left gave Michigan State a 67-64 lead, and Russell Byrd's 3 with 34 seconds put Michigan State up by six.
Iowa still had a chance to force a second overtime, but Mike Gesell missed a driving layup at the buzzer.
Devyn Marble had 21 points for Iowa (16-5, 5-3), including a layup with 6 seconds left in overtime that snapped the Hawkeyes' streak of 14:50 without a field goal.
"I just didn't think we were tough enough. We weren't tough at all," Iowa coach Fran McCaffery said. "I think they were being nice."
The Hawkeyes boast one of the nation's deepest benches, and they kept threatening to run away from the undermanned Spartans early in the second half.
Michigan State wouldn't let it happen.
The tough-minded Spartans had an answer for nearly every basket that could have swung the momentum back in Iowa's favor.
Iowa led 57-51 with 5:58 left, and its crowd began to sense the win. But Appling - with his shooting wrist heavily taped - hit a 3, and a layup and dunk by Costello made it 58-57 Spartans.
"We have guys that want to win," Appling said. "I feel like this win speaks volumes of the character of our team. We have a lot of guys that are able to dig down and compete. And at the end of the day I feel like that's what gave us the victory."
The Hawkeyes had a chance to win in regulation, but Marble missed a runner just before the buzzer.
That was a theme that doomed the Hawkeyes.
Aaron White had 10 points for Iowa, which lost despite hitting 19 more free throws than Michigan State.
"I felt like we were moving the ball well. We had some really good looks at it and just didn't make any," McCaffery said.
What made the loss even tougher for Iowa was it had been nearly a decade since Iowa City had seen a game this big.
Iowa hadn't hosted a Top 25 opponent as a ranked team since 2006, when it last went to the NCAA tournament. Even Iowa Gov. Terry Branstad made the 2-hour drive from Des Moines to see the program's biggest home game in years.
The Hawkeyes looked like the tighter team early. But the Hawkeyes hung close by building what would end up being a 43-20 edge in free throw attempts.
The second half and overtime proved to be a physical, back-and-forth affair between two teams with serious aspirations of a Big Ten title.
In the end, it was the Spartans who pulled out a game with 16 lead changes, 11 ties and one seemingly inexplicable shooting drought from the typically high-scoring Hawkeyes.
In victory, Michigan State also showed Iowa how slim the margin between contending for a Big Ten title and winning it can be.
"We've had games where we could have (showed resolve), but we didn't. This is the first game where we've had the opportunity and we've carried through," Costello said.