GREEN BAY, Wis. - After watching his team hold off No. 11 Butler for one of the biggest victories in school history, the first thing Wisconsin-Green Bay coach Tod Kowalczyk told his players was to get on the court and celebrate with a small but enthusiastic swarm of students.

And with good reason—Monday’s 75-66 victory was the third victory over a ranked team in school history.

But that doesn’t mean Kowalczyk is content with taking down a Horizon League heavyweight. Monday’s victory was the biggest step yet in what is shaping up as a surprising season, but Green Bay has bigger goals in mind.

“It just feels good to have a statement win, and we’re not done yet,” Ryan Tillema said.

Tillema scored 21 points, including 18 in the second half. But despite carrying a reputation for high-powered offense into Monday’s game, Green Bay (18-6, 10-2 Horizon League) pulled off the upset mostly through free-throw shooting and defense.

Green Bay was 32-for-35 from the line—with all but two of their free throws coming in the second half—and forced 16 Butler turnovers while committing four.

“I think it shows that we can win in other ways,” Kowalczyk said. “We grinded it out.”

Gordon Hayward had 22 points for Butler (19-2, 10-1), who came into Monday’s game cruising along with 11 straight victories in what was supposed to be a rebuilding year for the mid-major powerhouse.

But while Green Bay might be a surprise to the rest of the league, Butler coach Brad Stevens said he knew his team was in for a tough night.

“I knew who we were coming to play,” Stevens said. “They’re a really good team.”

Green Bay’s season began with back-to-back losses, but they’ve won eight of their past nine—their lone loss coming at Butler last month—and have surged to second place in the conference standings.

And they’ve broken a nine-game losing streak to the Bulldogs.

Butler players said the loss would be a learning experience, especially for young players.

“Every night we expect everybody’s best shot,” Butler’s Willie Veasley said. “We know that they’re a good team, and coming to Green Bay we knew it was going to be tough.”

Green Bay came into Monday’s game leading the conference in points per game, field goal percentage and 3-point percentage. They shot 35.2 percent from the field on Monday, but more than made up for it at the free-throw line.

Green Bay took control with a 10-2 run early in the second half—with all of Green Bay’s points coming on free throws.

With Butler already trailing 38-36, Tillema was fouled on a 3-point attempt by Tillema. He hit all three foul shots, and Terry Evans added another two free throws to put Green Bay up 43-36.

Tillema then drew another foul on the 3-point attempt and sank another three free throws to extend the lead to eight.

Butler’s Matt Howard scored inside to end the run, but picked up his fourth foul on the other end and Mike Schachtner hit two free throws to give Green Bay a 48-38 lead.

The foul calls kept coming Green Bay’s way, Butler couldn’t sink a shot of its own and an upset appeared imminent.

“The refs are what they are,” Howard said. “I didn’t see everything. I’m not saying that they weren’t fouls, I’m saying I didn’t see every play. I know we were playing physical. Both teams were and it is what it is.”

Tillema said the calls were justified.

“We were being aggressive, and getting rewarded,” Tillema said.

Butler later was called for yet another foul on a 3-point attempt and Troy Cotton hit all three free throws to build a 58-45 lead with just under seven minutes left in the game.

But Butler rallied with an 8-0 run and later cut the lead to four on a fast-break slam dunk by Gordon Hayward, but Ronald Nored fouled out and Tillema hit both free throws to put Green Bay up 63-57 with 3:17 left.

Cotton then hit a 3-pointer with 2:10 remaining, and Green Bay was 9-for-10 from the free-throw line in the final 1:25. Cotton scored 19 points for the game.

With Monday’s victory, Green Bay has a 3-27 all-time record against ranked opponents. It is Green Bay’s first victory over a ranked team since beating Miami of Ohio in 1998.