Illinois took advantage.
The Hoosiers' season-high 23 turnovers, more than twice as many as the Illini, ruined what could have been an impressive Big Ten debut. They lost 83-80 in overtime.
"Turnovers were a huge difference in the game," IU coach Tom Crean said. "We have to continue to work on that."
One of the biggest turnovers came after freshman Noah Vonleh grabbed a missed free throw and the Hoosiers trailing 78-75 with 25 seconds left in overtime. Make a good outlet pass to teammate Will Sheehey and who knows what might have happened.
But Illinois' Jon Ekey knocked the ball loose for a turnover and the Illini would hang on.
"I looked quick; I saw Will," Vonleh said. "I didn't see the guy coming. He came in there and just took the pass away. I've just gotta be more aware next time."
Yogi Ferrell had a career-high 30 points and four assists. Vonleh had 16 points and nine rebounds. Evan Gordon had 10 points.
The previously three-point-shooting challenged Hoosiers (10-4) had a season-high 10 three-point baskets.
It wasn't enough.
"We fought; we battled," Crean said. "It was the first type of game in this environment for so many of our guys. We didn't get the result we wanted. We still have things have to improve. With all that, with all the turnovers, we were right where we needed to be right until the end."
Illinois (12-2) was led by Rayvonte Rice's 29 points and eight rebounds.
"it was a high-level game, a big-time game," Illini coach John Groce said. "It came down to players making plays.
"We've got some tough dudes. We take a lot of pride in that. But to (Indiana's) credit, they do, too."
Illinois opened with an 8-3 lead. IU countered with a 7-0 run and still led 13-11 when a turnover flurry allowed the Illini to gain eight points of separation. The Hoosiers rallied back.
In the final minute, Rice intercepted a sloppy Sheehey pass and drove for a layup. Sheehey fouled him and Rice hit the free throw. Sheehey countered with a last-second three-pointer for a 39-39 halftime tie.
The Hoosiers, previously a poor three-point shooting team, were 6-for-12 beyond the arc, plus 9-for-10 from the line. That enabled them to overcome 13 turnovers.
Vonleh was huge with 13 points, five rebounds and two blocks. Ferrell had 10 points and four assists.
After a series of second-half ties, the Hoosiers pushed ahead 59-52 on Perea's three-point play and Ferrell's third three-pointer.
Illinois countered with an 11-2 run to take a 63-61 lead. IU shot back ahead by four. Illinois squeezed ahead by two.
IU forged a 71-71 tie and then had a chance to win at the end of regulation, but Gordon missed a jumper at the buzzer.
"We couldn't have gotten a better shot at the end of regulation," Crean said. "It just didn't go in. It was a great look. We practice those situations all the time."
The Hoosiers never led in overtime.
"We fought like crazy," Crean said. "That kind of hustle and effort and intensity is going to carry them a long way."