First-year coach Chris Collins kept waiting for Northwestern to discover an identity.
The Wildcats began the year with hopes of a first-ever NCAA tournament berth, then saw a brutal offense quickly put their season on the ropes.
Collins delivered a hard message, one that was clearly received on Saturday afternoon.
A suffocating defense kept the Wildcats in the game and reserve guard Tre Demps reeled off a late scoring flurry to lead Northwestern past Indiana with a scrappy, hard-fought 54-47 upset.
"We've found ourselves," said Collins, a first-time head coach. "We said, 'If we're going to make something out of this year, we've got to become a blue-collar team.' It takes time to figure out."
The Wildcats (9-10, 2-4 Big Ten) grasped Collins' vision and executed it to perfection, nudging quick-paced Indiana into a knock-down, drag-out slugfest.
When it was all over, center Alex Olah, a dominating physical presence on the back line, raised both arms in the air and blew a kiss to purple-clad fans behind the Northwestern bench.
"We learned," Olah said. "It's not just my defense. We had to get back in transition, always two guys back. Then we had to stop them getting in the paint. We're just playing hard."
As a result, the Hoosiers (12-6, 2-3) suffered a letdown after beating previously No. 3-ranked Wisconsin on Tuesday. Center Noah Vonleh led Indiana, which shot just 25 percent from the field, with 17 points and 12 rebounds, his seventh double-double.
Yhe other four starters combined for just 18 points on 6-of-34 shooting from the floor as the Hoosiers suffered from an amazing inability to make shots.
"We have a long way to go," Indiana coach Tom Crean said. "I can't just put it on youth. We did not have the hunger. Northwestern did."
Northwestern led most of the way and received 15 points from Demps, including 13 straight that gave the Wildcats a 48-42 lead with 47 seconds remaining.
"Tre was tremendous," Collins said. "He carried us down the stretch. I like that attitude."
After leading by nine in the first half, Northwestern trailed 38-35 before Demps exploded, outscoring the Hoosiers 13-4 during a period of nearly six minutes.
After his 3-pointer and jumper, Indiana point guard Yogi Ferrell made two free throws to tie it at 40. Demps, a sixth man averaging 10.3 points per game, responded with another 3-pointer and a driving layup past Ferrell to give Northwestern a 45-40 edge as Crean called timeout with 2:21 left.
"I love Coach," said Demps, who was 1 of 5 from the field in the first half before making shots on four consecutive possessions in crunch time. "As long as we're fighting, he'll always have our back. Everybody has confidence in me, so I shot it again."
Forward Drew Crawford had 17 points and 12 rebounds for the Wildcats, who shot 37 percent from the field and snapped a stretch of five losses in six games. Olah had eight points, eight rebounds and six blocks.
A defense with quality size and mobility combined with quick reactions was at its best, forcing Indiana into bad shots, stymieing post plays and altering shots at the rim. It held Ferrell, Indiana's leading scorer, to nine points on 2-of-14 shooting from the field.
"Some jump shots, I think we did force; I know I did personally," Ferrell said. "They just packed the paint, really."
It was a defensive struggle from the start. The teams combined for 14-of-60 shooting from the floor and 10 turnovers in the first half. The Wildcats were first to reach double figures when Crawford's basket with 8:50 remaining gave them a 10-6 lead.
A running floater in the lane by Demps -- whose father, Dell, is general manager of the New Orleans Pelicans -- pushed the Wildcats ahead 17-8 with 3 1/2 minutes left in the half before Indiana generated rare momentum.
Austin Etherington completed two three-point plays, letting out a roar and fist pump after the second, as the Hoosiers closed on an 11-5 run to trail 22-19 at intermission.
But the gritty Wildcats never lost their intensity or composure and completed a stunner.
"We're trying to build a program," said Collins, a Duke assistant for 13 years and the son of former NBA coach Doug Collins. "We're in the early stages. Offensively, it's a work in progress. Sometimes if you don't see the fruits of your labor pay off, you get discouraged. But our guys dug down."
NOTES: Northwestern F Drew Crawford, a career 1,600-point scorer, is the Big Ten's active leader in that category. ... The Wildcats have won three of their last five visits to Assembly Hall. ... Indiana F Jeremy Hollowell, a starter for 14 games, continued to sit out while he manages what coach Tom Crean described as "focus" issues. "You'll see him when I put him in," Crean said. ... Northwestern G Dave Sobolewski has missed the last three games because of a concussion. Coach Chris Collins started F Kale Abrahamson in Sobolewski's place and said the bigger lineup might remain in place even when Sobolewski returns.