BLOOMINGTON, Ind. (AP) - North Dakota State challenged No. 1 Indiana at every turn Monday night.

It still wasn't enough.

The Hoosiers turned the game with a 23-point second-half scoring flurry, finally pulling away from the pesky Bison 87-61 in the Progressive Legends Classic.

"We had some fight in us, but not enough," coach Saul Phillips said. "It's amazing to me, they just kept coming at us in waves. Eventually, they leaned on us and a leg went out."

They certainly tried to go toe-to-toe with the nation's best team.

By contesting every shot the Hoosiers took, regardless of the consequences, North Dakota State (1-1) never allowed the Hoosiers offense to get in sync. And with some timely outside shooting, the Bison were still within 48-38 early in the second half.

But they ran out of steam, bodies and eventually wore down.

Marshall Bjorklund, who scored 16 points, and Mike Felt, who had 11, both had to leave with leg cramps, and that left the Bison without much chance against the Hoosiers size or depth.

"You know you're having a bad night when they both cramp up within five minutes of each other," Phillips said. "I haven't had a player cramp up on me since I've been here and two of my best players go down in five minutes."

The Hoosiers took full advantage.

This was the kind of game that had given Indiana problems in previous seasons. Fans, and perhaps Indiana's players, figured those struggles were over since the Hoosiers (2-0) reclaimed their spot on top of the college basketball world.

But North Dakota State proved how dangerous assumptions can be.

And had it not been for the second-half lift from Cody Zeller, Remy Abell and Jeremy Hollowell who knows how this game may have gone.

Coach Tom Crean certainly wasn't happy.

"Your fundamentals, your technique, all your experiences, all those things are really, really important, but there's nothing bigger than energy and toughness. It's got to be there constantly," Crean said. "Once we got that figured out tonight and we had some guys that figured it out from the beginning, but we didn't have a team of guys that figured it out from the beginning, and once we did, I thought we played pretty well."

North Dakota's defense did take a toll on the Hoosiers.

When the Hoosiers couldn't get their up-tempo, inside-out game in sync, the offense sank. The grind-it-out style made Indiana look like, well, ordinary.

Their outside shooters were just 4 of 11 from the 3-point arc in the first half and 1 of 2 in the second half. The energy that persisted throughout Friday night's season-opening rout over Bryant was missing, too.

Crean was flummoxed.

"There's conventional, there's unconventional and then there's tonight," he said. "We need to do the same thing next Monday and Tuesday. We've got to do the same thing against Ball State and North Carolina. It makes no difference."

Crean learned that lesson the hard way against the same North Dakota State program six years ago. Back then, the Bison rolled into Milwaukee, upset No. 8 Marquette 64-60 and returned home with the Golden Eagles' tourney trophy. They haven't beaten a Top 25 team since.

So before Monday night's game, Crean warned his players not to overlook the Bison. It didn't exactly reverberate until halftime when they were holding a 42-29 lead.

"We're going to see everything from different teams this year," Zeller said after scoring 22 points and grabbing nine rebounds. "I know they're going to try different strategies, that they're going to try to outphysical me, outphysical some of our other guys, try to get us in foul trouble, so you've just got to keep your composure and keep on working."

And it was the young guys who responded.

Abell, a sophomore, made all five of his shots including three 3-pointers to finish with a career-high 14 points. Hollowell, a freshman, scored 14 points in 19 minutes, and freshman point guard Yogi Ferrell was a defensive beast.

Yet, with 15:55 to play, the Bison were still within 48-38.

That's when the Hoosiers turned the game.

Hollowell started the key run with a three-point play and two free throws. Abell followed that with another free throw and a layup and Zeller had added consecutive dunks.

Will Sheehey then hit a 3, Abell made two more 3s and closed out the run with a putback to give Indiana a 71-51 lead. That was all the Hoosiers needed Monday.

"If we're going to be successful, we've got to have a group of guys where there's very little drop off when we got to the bench," Crean said. "Tonight, we just played."