WEST LAFAYETTE, Ind. -- Purdue is a Top 25 team in large part because of senior center A.J. Hammons, sophomore center Isaac Haas and freshman power forward Caleb Swanigan.

Led by Hammons' 18 points and 12 rebounds, eight points and four rebounds from Haas and four points and seven rebounds from Swanigan, the No. 17 Boilermakers got 30 points and 23 rebounds from their talented post players on Tuesday in a 71-61 victory against guard-oriented Northwestern in Mackey Arena.

However, without a career-best 15 points from fifth-year transfer guard Johnny Hill and 11 from freshman shooting guard Ryan Cline, each of whom came off the bench, Purdue may have struggled to improve to 21-6, 9-5 in the Big Ten.

The Boilermakers, who were coming off a 61-56 loss Saturday at Michigan, led only 56-50 in the second half when Cline and Hill made consecutive 3-pointers, extending the advantage to 62-50 with 5:43 to play.

"Their physicality put a lot of pressure on us, but Cline's 3 was the biggest shot of the game, and then Johnny Hill made one to stretch their six-point lead to 12 just when we were getting into deep foul trouble," Northwestern coach Chris Collins said.

The Wildcats were outscored 21-5 from the free throw line and were outrebounded 45-24, with Hill and Cline combining for 10 rebounds, three assists and only one turnover.

"Those two 3-pointers allowed us to get going on offense down the stretch," said Hill, whose previous Purdue high was 13. "Then that offense translates into defense. I have been hitting my 3s in practice, but until tonight, I really hadn't done that in a game."

Cline understood the significance of those shots on a night when the Boilermakers were 4 of 13 from 3-point range.

"That was a big turning point in the game, but overall, our defense is what won it for us," Cline said.

Northwestern (17-10, 5-9) got 16 points from shooting guard Trey Demps, 14 from point guard Bryant McIntosh and 12 from center Alex Olah.

Northwestern pulled to within 41-37 with 14:02 remaining on McIntosh's jumper. Purdue countered with a 21-13 run to take a 62-50 lead with 5:43 remaining on Hill's 3-pointer.

The Boilermakers went almost 11 minutes during a second-half stretch with one field goal -- Hill's layup -- yet maintained an advantage by making 12 of 14 free throws in that pivotal sequence.

"The two big 3-pointers gave us a little distance," Purdue coach Matt Painter said. "Northwestern is a tough matchup for us. Our ability to get to the free throw line in the second half was huge, too. We wanted to crash the glass and get to the free throw line.

"I also thought Johnny Hill played really well. Until he got here (from Texas-Arlington) he had never gotten to play with size. He has had to learn to play with all of our size -- feeding the post instead of driving the ball to the basket -- and that has been an adjustment."

The Wildcats outscored Purdue 10-4 during the final 3:18 of the first half to slice a 14-point deficit to 35-27 through 20 minutes.

The Boilermakers ran out to an early 8-0 lead when Northwestern missed its first eight field goal attempts. The Wildcats were 7 of 26 from the field before making five of their final six during the half-ending burst.

Hammons' 11 points led all scorers at halftime while Demps had 10 for Northwestern, all during the final 8:37.

Four 3-pointers and a three-point play accounted for 15 of the Wildcats' 27 first-half points. Purdue made only one first half 3-pointer, that by Cline with 9:34 to go in the half.

The Boilermakers outrebounded Northwestern 26-15 in the opening half, getting eight from Hammons and five from freshman power forward Caleb Swanigan.

NOTES: Northwestern was playing the second contest in a four-game sequence of Big Ten single plays, having beaten Illinois on Saturday and with Michigan and Rutgers next up. ... The Wildcats were 6 for 27 from 3-point range, snapping a four-game streak of making at least nine. ... Purdue entered the game leading the Big Ten in scoring defense at 63.6 points per game. ... Swanigan and Hammons entered ranked first and third, respectively, in Big Ten rebounding at 8.6 and 8.0.