Dunham went 10 for 10 at the line on his way to 24 points, and Butler beat DePaul 67-53 on Saturday to move into sole possession of second in the Big East.
Roosevelt Jones had 16 points and Kameron Woods finished with 14 for the Bulldogs (21-8, 11-5), who have won five of seven. Butler committed 18 turnovers, but connected on 22 of 27 foul shots, compared to 6 for 10 for DePaul.
"Our ability to get the line was important," coach Chris Holtmann said. "That's what we've done most of the year."
Coupled with Georgetown's 81-70 loss at St. John's, the Bulldogs moved one game ahead of the Hoyas for second in the conference behind No. 6 Villanova. They host Georgetown on Tuesday night.
"DePaul was our sole focus. We didn't talk about anything else," Holtmann said. "We have not talked about league standings or where we're at or anything beyond that. We'll talk about tomorrow about how we can play better, and then we'll start to prepare for Georgetown."
Jamee Crockett scored 20 points for DePaul (12-18, 6-11), which has dropped six in a row.
DePaul scored the first nine points of the second half to move in front for the first time. The Blue Demons then grabbed a 38-32 lead on Billy Garrett's layup with 14:35 remaining, but a costly technical foul on coach Oliver Purnell sparked a 30-5 run for the Bulldogs that put the game away.
"I was complaining about a moving screen, and a guy said 'Move back into the box and complain,'" Purnell said. "So I moved back into the box and complained and got hit with a technical."
Dunham and Jones started the decisive stretch with two free throws apiece. Dunham made a tying 3-pointer with 12:18 remaining, and had another 3 to make it 56-43 with 7:59 to go. Jones then scored four straight points and Woods capped the surge with a jumper.
The Blue Demons shot 40.8 percent (20 for 49) and were hurt by a 36-19 rebounding deficit.
"We weren't executing our offense," Crockett said. "People had their different own agendas. People weren't fighting hard, so when you do that against a good team, a ranked team, they take advantage of that."
DePaul got off a slow start, but ripped off a 10-0 run to tie it at 24. Dunham then scored the last five points of the period on a jumper and three foul shots after he was fouled on a 3-point attempt for the second time in the half.
"If I'm aggressive enough to be able to take the shot, and then they're closing out too hard that they foul me, then they're thinking about that throughout the game," Dunham said. "So I think it's a huge opportunity for me."
Dunham was 6 for 11 from the field in 34 minutes. He averaged 19.7 points on 52 percent shooting in seven February games.
"I've been able to hit a few more shots in the sets that we run for me," he said. "The game is a lot easier playing with guys like Roosevelt and him getting in the lane. Like coach says, the paint touches, it's constantly getting the defense to retreat and things like that, which opens it up for me."
DePaul guard Billy Garrett, Jr. appeared to hurt his back on a drive to the basket in the second half. He tried to play through the injury and finished with seven points.
"I think he's OK," Purnell said. "I'm sure he'll be sore. We'll check him out, but I think he's OK."
Butler: The Bulldogs have won their last three games against the Blue Demons, but trail 6-4 in the overall series.
DePaul: The Blue Demons honored seniors Crockett, Greg Sequele and Forrest Robinson before their final home game, and then recognized former star Quentin Richardson at halftime. Richardson is part of the 2015 class for the school's athletic hall of fame. ... DePaul went 7 for 18 from beyond the arc while breaking the school record for 3-pointers in a season. This year's team was tied with the 2007-08 squad with 231 3s coming into the game.
Butler hosts Georgetown on Tuesday night.
DePaul visits Marquette next Saturday.
Jay Cohen can be reached at http://www.twitter.com/jcohenap
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