In the end, the Hoosiers survived, 72-68.
Victor Oladipo clinched it with a pair of free throws with 2.8 seconds left.
IU (24-3 overall) took sole possession of the Big Ten lead with a 12-2 record to Michigan State's 11-3. Because the Hoosiers swept the Spartans, they also hold a tie-breaker edge, giving them, in essence, a two-game lead.
Oladipo overcame an ankle sprain to total team highs in points (19), rebounds (nine) and steals (five). Cody Zeller added 17 points and five rebounds. Jordan Hulls and Christian Watford each had 12.
Michigan State (22-5) was led by Gary Harris' 19 points. Adreian Payne added 17 points and seven rebounds.
The first half settled nothing, but positioning. IU led 36-30. It took Michigan State seven minutes to make that disappear. It took the final 13 minutes to determine a winner and, perhaps, a Big Ten champion.
The Hoosiers had just enough to win their fourth straight game. They have a week to savor it before traveling to Minnesota next Tuesday.
Michigan State has to regroup for a brutal road swing of at No. 18 Ohio State and at No. 7 Michigan.
Passion flared in the closing minutes when Michigan State forward Derrick Nix, he of the Zeller-and-Oladipo-are-overrated comments, delivered an apparent cheap shot to Zeller. Officials checked the replay monitor, but called nothing.
IU point guard Yogi Ferrell's first-half impact had less to do with his offense (still impressive with six points, four assists and three rebounds) and more with his defense. He held point guard Keith Appling to two points on 1-for-5 shooting. Appling also had one assist and two turnovers.
Appling finished with six points and four turnovers.
Zeller established right away he wasn't going to get into an in-the-paint wrestling match with Michigan State big men. He took mid-range jumpers and drove to the rim from the perimeter. He also missed three one-footers. Still, his eight first-half points were crucial in IU getting and maintaining an early lead. The Hoosiers led by as many as eight before settling for a 36-30 halftime advantage.
IU surged ahead 48-42. Michigan State's 7-0 got it a one-point lead, that could have been more if not for Hulls hustling back on defense to draw a charge, and Zeller muscling in for a three-point play.
The Hoosiers built another six-point lead by attacking the basket. Payne's three-point shooting kept the Spartans close.
There would be no separation.
Nix scored four straight points to give Michigan State a 67-63 lead. IU lost its offensive efficiency.
Then it found it.
Watford converted a three-point play. Oladipo tipped in a Ferrell miss. IU led 68-67 with 39.5 seconds.
Michigan State botched its possession. The Hoosiers had 13.8 seconds to burn.
Watford inbounded long to Oladipo for a dunk and a 70-67 lead.