The Hoosiers (12-9-1) advance to the third round where they will face No. 5 seed North Carolina (14-2-3) on Sunday in Chapel Hill, N.C.
"I want to compliment Butler on a tremendous year," said IU coach Mike Freitag. "They are very well coached and these local games in the first rounds of the tournament are always tough. I don't think we played particularly great today, but we found a way to win. That is what we have done lately and we intend to keep doing the same thing. I am proud of the way we played. We fought hard and kept our focus. It wasn't always pretty, but we got the job done."
Indiana finished the match with just nine shots but got all the scoring it needed at 57:25. Darren Yeagle, who has been a force for the Hoosiers in NCAA Tournament play, set up the score with a cross to Bruin on the back post. Bruin went unmarked as the ball sailed over BU goalkeeper Fabian Knopfler, and he touched the ball into the lower left. It is Bruin's fifth game-winning goal of the year.
"Darren has had a great last couple of games," Freitag said. "And it was nice to see (Will) get on the end of one. Everyone worked hard today.
The first half was a defensive battle with the Bulldogs holding a slight 3-2 advantage in shot attempts. Indiana's best chance in the first half didn't even result in a shot when Eric Alexander passed the ball up to Yeagle, who then tried to slide the ball over to Bruin 12 yards from the net. Knopfler came off his line and broke up the pass to keep things scoreless.
Redshirt freshman Luis Soffner recorded his ninth shutout of the season, thanks in large part to a brilliant diving save to his right off a shot from Matt Hedges in the 50th minute. Soffner finished the game with three saves.
Bruin finished the match with two of the Hoosiers' five shots, along with one each from Andy Adlard, Yeagle and Lee Hagedorn.
The Hoosiers are making their second-straight trip to the NCAA Round of 16 and third in the last four seasons. Indiana and North Carolina last matched up in the NCAA Tournament in the 2001 College Cup title game, a 2-0 victory by the Tar Heels.