INDIANAPOLIS -- All Butler guard Alex Barlow saw Saturday was space and an opportunity to make a play.

So the unlikeliest player on the floor took a chance and made the biggest shot of the game.

When Indiana's defenders failed to converge on the 5-foot-11 walk-on, Barlow kept right on going through the lane, drove to the basket and hit a spinning 6-foot jumper with 2.4 seconds left in overtime Saturday to give the Bulldogs another stunning upset -- 88-86 over No. 1 Indiana in the Crossroads Classic.

"The floater is a shot I work on a lot and I happened to get a lucky bounce," Barlow said. "It was a good feeling."

Luckily for the Bulldogs (8-2), Barlow was on the floor.

The kid who spurned college scholarship offers to play his best sport, baseball, and opted to come to Butler for only one reason -- to learn how to coach basketball from Brad Stevens -- showed everyone he can hoop it up, too.

Stevens didn't hesitate to constantly keep the ball in Barlow's hands after three key Butler players had already fouled out. The sophomore who had scored only 12 points in nine games this season and 18 in his college career delivered with a series of key plays.

Barlow finished with a career-high six points, came up with a big steal that led to a go-ahead 3-pointer late in overtime and finally won it with a shot that bounced off the back of the rim, straight into the air and finally through the net.

Indiana (9-1) immediately called timeout to set up a play but could only muster Jordan Hulls' heave from near half-court, a shot that faded to the left of the basket and suddenly the first college in Indiana to go to back-to-back Final Fours had another school first -- its first win in five tries over a No. 1 ranked team.

The sold-out arena roared as the game ended, and the Bulldogs rushed to midcourt where they celebrated with Barlow.

"I thought he just rose up over Hulls and it looked good," Stevens said. "Don't use this as an excuse to get down on Indiana. I still think they're the team to beat in April. Our guys just played really hard and when it really mattered, they figured out a way."

Butler (8-2) has now won six straight at Bankers Life Fieldhouse, better known as the home to the NBA's Pacers, and four of the last five when this series been played in Indianapolis. The Bulldogs have wins over Marquette of the Big East, North Carolina of the ACC and back-to-back victories over Northwestern and Indiana of the Big Ten.

And Barlow, the surprising star, overshadowed a supporting cast that had strong games, too.

Roosevelt Jones scored 16 points and matched his career-highs with 12 rebounds and six assists before fouling out with 2:03 left in regulation.

Andrew Smith finished with 12 points and nine rebounds and held national player of the year candidate Cody Zeller in check until fouling out just 17 seconds after Jones.

Rotnei Clarke, who transferred to Butler from Arkansas, scored 13 of his 19 points and made three of his five 3-pointers in the second half.

In all, five Bulldogs players finished in double figures while the defence held one of America's most proficient offences to just 42.9 per cent shooting from the field.

"We cost ourselves at the end of the game defensively," coach Tom Crean said after waiting more than an hour to take questions. "They made the plays, there's no question about that. But we made the mistakes on how we guarded them."

The Hoosiers were led by Cody Zeller, who had 18 points, including a layup to tie the score at 86 with 19.3 seconds left in overtime. Victor Oladipo also had 18 points and Will Sheehey scored 13 points off the bench.

But the Bulldogs grabbed 19 offensive rebounds and outrebounded Indiana -- the first team to do that this season.

Clearly, this was not the same Indiana team that won its first nine games by an average of nearly 32 points while shooting 51.5 per cent from the field.

"There's a lot of things," said Zeller, who had only five rebounds and four baskets. "We got outrebounded. There's a lot of little things that we have to figure, but we'll get back to work and figure them out."

The difference Saturday was that Butler never let the Hoosiers get away from them -- even when Smith and Jones went to the bench with four fouls midway through the second half.

Stevens reinserted both players with 9 minutes to go in regulation, trailing 57-50, and the Bulldogs responded with a 12-0 run that gave them a 66-59 lead with 4:31 left in regulation.

Butler still led 71-64 when Jones fouled out, and the Hoosiers answered with five straight points from the free-throw line. They finally tied the score on Yogi Ferrell's 3-pointer from the right wing with 6.1 seconds to go, and Butler's Chase Stigall missed a 3-pointer off the front of the rim as time expired.

In overtime, Indiana looked like it would take control when Zeller's layup made it 84-80 with 2:12 to play.

But the Bulldogs again rallied, getting a 3 from Clarke, a steal from Barlow that led Stigall's 3-pointer, and Barlow's improbable winning shot.

"I just figured I would throw it up to the rim," Barlow said. "If I missed it, I knew they wouldn't get a shot off. Luckily, it bounced in."