CARBONDALE, Ill. (AP) -- A.J. Graves struggled on offense for most of the night. When it counted the most, he came through.
The senior guard sank a 35-foot shot at the buzzer to lift Butler (No. 17 ESPN/USA Today, No. 16 AP) to a 57-55 win over Southern Illinois on Friday night.
Graves came into the game as the leading scorer for Butler (12-1). But Southern Illinois (5-6) held him to seven points over 33 minutes until the final play.
Butler coach Brad Stevens called the play to go to guard Mike Green, Graves said. But when Green wasn't open, the play shifted to Graves.
"It's a play we know a lot about," Graves said. "Coach actually called it wrong, but we got it taken care of and that is what we are supposed to do."
Wesley Clemmons made a 3-pointer with just more than a minute remaining to give the Salukis a 55-52 lead. But Green countered with a layup for the Bulldogs.
Southern Illinois' Tyrone Green then missed a free throw, setting the stage for Graves' shot.
Mike Green led Butler (12-1) with 19 points. Matt Howard added 15 and Graves finished with 10.
"In an environment like that, you have to be extremely tough," Stevens said. "You have to have anybody on your bench and anybody wearing Butler blue to be on the same page. I thought our guys were very tough and we stayed together."
Matt Shaw, Southern Illinois' leading scorer, was held without a basket. He went 0-for-7 from the field and missed both of his free-throw attempts.
Butler survived a second-half span of almost 14 minutes without a field goal. The Bulldogs went 12-for-18 from the free-throw line after halftime and made 21 of 30 free throws for the game.
The Salukis were 3-for-12 from the free-throw line.
Southern Illinois coach Chris Lowery said his team executed the game plan but couldn't overcome the free points off of fouls.
"This is our kind of game," Lowery said. "They shot 30 free throws, which is a lot in our building, but you can't go 3-for-12. That's awful. We have to make those free throws."
Butler put together an 8-0 run late in the first half and led 31-29 at halftime.
The loss continued a tough December for the Salukis, who have won just two of their last eight games. Southern Illinois, which had been ranked in the Top 25 heading into the season, is now 5-6 heading into conference play.