Cody Zeller collected a game-high 24 points and four teammates also scored in double figures as top-seeded Indiana opened Big Ten tournament play with a 80-64 victory over Illinois.
The Hoosiers (27-5), who earned a first-round bye after winning the regular-season championship, advanced to Saturday's semifinals as Chris Watford scored 15 points, Victor Oladipo and Kevin "Yogi" Ferrell each had 12 while Will Sheehey added 11. Oladipo also had a game-high 11 rebounds.
Brandon Paul and Tracy Abrams each had 16 points as the eighth-seeded Illini shot just 34.5 percent from the field (20 of 58). Joe Bertrand added 10 points.
Indiana will meet Wisconsin, which beat Michigan 68-59 on Friday, in Saturday's semifinals at the United Center.
The Hoosiers, ranked No. 3 nationally, made a case for a top seed in the upcoming NCAA tournament as they jumped to a big early lead and never trailed.
Indiana maintained double-digit leads through most of the second half and hit a high-water mark of 20 points with 53 seconds to play after a Ferrell layup.
The Hoosiers and Illini met only once previously this season, a 74-72 Illini victory over then top-ranked Indiana on Feb. 7 in Champaign
The teams were a collective 2 of 15 from the field through the first six minutes until Sheehey hit a baseline 3-pointer for an 8-2 Indiana lead. He added a shorter jumper 42 seconds later to make it 10-2.
Illinois went 6:41 between field goals before Bertrand broke the drought on a fast-break layup at with 11:32 showing.
Zeller reached 10 points for the game with 7:33 left in the half on a steal and fast-break layup that gave Indiana a 22-7 lead.
He closed the half with 14 points as Indiana opened a 35-21 lead. Paul had nine for the Illini, who shot 25.9 percent from the field (7 of 27).
Illinois' shooting improved in the second half, but the Illini weren't able to trim the deficit despite Abrams' 10 points in the first 9 1/2 minutes. Illinois never cut Indiana's lead below 10 points in the span.
The Illini got within eight at 60-52 on Richardson's two free throws with 8:17 left. But the Hoosiers responded with an Olapido layup and a Watford 3-pointer to boost the lead back to double digits at 65-52 with 5:31 left.
Zeller was 9 of 11 from the field (81.8 percent) and the Hoosiers were 27 of 50 (54 percent). Indiana also had a decisive 38-26 rebounding advantage.
NOTES: Indiana has 21 Big Ten championships, but this was the first time in the 16-year tournament that the Hoosiers were the No. 1 seed. ... Indiana finished 14-4 in Big Ten play on the way to its first outright regular-season title since 1993 and is 10-15 all time in conference tournament play. ... The No. 1 seed is 9-2 all time against the No. 8 seed. ... Illinois has won the most tournament games of any team with a 24-14 record and has the second-best winning percentage (.631).