WEST LAFAYETTE, Ind. -- Robbie Hummel's back appears to be fine.
The sophomore forward missed Purdue's previous game, a loss to Penn State, with back spasms. He returned to score 11 of his 16 points in the second half as the No. 14 Boilermakers beat Wisconsin 65-52 on Sunday afternoon for their first Big Ten win.
Hummel, the league's preseason Player of the Year, made four of eight 3-pointers and had five rebounds in 28 minutes.
"The first half, I was a little iffy," he said. "The second half, I got more confident."
Hummel hit his lower back hard on the floor in the first half, but he said it wasn't a problem.
"The adrenaline kicked in," he said. "To be honest, I feel really good. I didn't feel any pain."
Purdue defensive stopper Chris Kramer, who missed the Penn State game with a sprained left foot, played 21 minutes. Kramer and Hummel both saw their first action about five minutes into the game.
Purdue, the Big Ten favorite, looked shaky in losses to Illinois and Penn State and was in danger of falling to 0-3 in the league. Wisconsin coach Bo Ryan knew Purdue would improve significantly with Hummel and Kramer.
"It gives you energy, you play off of it," he said. "They have Hummel and Kramer back, and they're back playing like the Purdue everybody knows. You have to give Purdue the credit today."
The Boilermakers committed just four turnovers, and only one in the second half. Hummel and Kramer finished without a turnover.
"I think they really helped us in a lot of aspects of the game," Purdue coach Matt Painter said. "Sharing the basketball, making the extra pass, they do a lot of the little things."
JaJuan Johnson had 20 points and 10 rebounds to lead the Boilermakers (12-4, 1-2 Big Ten). He scored Purdue's first six points.
"I thought J.J. really set the tone for us on the boards and scoring the basketball," Hummel said. "Sometimes, it's hard to get that first basket to fall."
Joe Krabbenhoft had 13 points and seven rebounds for Wisconsin (12-4, 3-1), which had won three in a row. Marcus Landry, Wisconsin's leading scorer, finished with nine points on 3-for-15 shooting.
Wisconsin had a chance to severely damage Purdue's chances at winning the conference. The Boilermakers finished second last year with three losses.
"We take it one game at a time," Krabbenhoft said. "There's the big picture right there. We take it game-by-game, and we'll just see how things end up at the end of the season."
Back-to-back dunks by Johnson gave Purdue a 25-11 lead with just under six minutes left in the first half. Johnson scored eight consecutive points for the Boilermakers in the 10-4 run.
Trevon Hughes and Jason Bohannon hit back-to-back 3-pointers for Wisconsin, Bohannon's with four seconds left in the opening half, to cut Purdue's lead to 32-26 at the break.
Johnson scored 14 points on 6-for-7 shooting in the first half. He also guarded Landry for much of the game.
"JaJuan is the most improved player on their team," Landry said. "He's a good, athletic big man. He's come a long way. He's gotten a lot stronger."
Wisconsin cut the lead to 34-30 early in the second half, but a bucket in close by Nemanja Calasan and a high bank shot by Kramer made it 38-30 just over four minutes into the second half.
Purdue led 41-34 before Hummel made a 3-pointer, Kramer made a layup and Marcus Green hit a 3-pointer from the left corner to give the Boilermakers a 49-34 lead and force a Wisconsin timeout. Purdue led by double digits the rest of the way.
Purdue outrebounded Wisconsin 34-29 after getting outrebounded 41-27 by Penn State.
"I think one of the things that really helped us with it being a must-win was how much of a bad taste we had after we [were] embarrassed rebounding against Penn State," Kramer said.
Wisconsin shot just 38 percent and made six of 20 3-pointers.
"Purdue took us out of some things we like to do," Landry said. "They were just more aggressive than we were. They really pressured us on the perimeter."
Now, the Boilermakers believe they still have a chance to win the league.
"Those losses really opened our eyes," Johnson said. "We had to come out and get a win to help us regain our focus for the rest of the season."