Kaminsky, a 7-footer who can shoot from the perimeter, went 4 of 5 from 3-point range for the Badgers (25-5, 12-5 Big Ten), who won their eighth straight thanks in large part to shooting 48 percent from the field in the first half.
Ronnie Johnson had 15 points for the Boilermakers (15-15, 5-12), who lost their fifth straight and fell into sole possession of last place in the conference.
Wisconsin attacked the lane early before starting to hit from the perimeter. The Badgers had a 16-point lead whittled to seven with 5 minutes left but were otherwise in firm control.
Johnson's transition layup got the Boilermakers within 58-51 before Sam Dekker converted a three-point play about 30 seconds later to revitalize the Badgers.
Wisconsin could have made it slightly easier by hitting a few more free throws in the second half, when they went 20 of 27 from the line. Kendall Stephens of Purdue hit a 3 from the corner just before time expired for the final margin.
The Badgers have had a few issues during their winning streak with keeping things interesting late. At least there was no repeat of last season's final game at the Kohl Center, which was spoiled by the Boilermakers with a 69-56 victory.
On Wednesday night, guard Ben Brust went home happy after his senior ceremony. He was lifted from the game with 21 seconds left, raising an arm to acknowledge the loud roars from the appreciative crowd.
The sharpshooter gave fans one last memorable 3 after hitting straightaway from about 23 feet in front of the "Grateful Red" student section.
Brust finished 3 of 11 from the field and 1 of 5 from long range. His long 3 made it 24-10 with 6:37 left in the first half of a game that at times took on the intensity level of a preseason exhibition.
The pace got choppy in the second half with several scrambles for loose balls and officials calling a combined 22 fouls.
After starting 6 of 10 from the field, Wisconsin went 17 of 42 (40 percent) the rest of the way. Kaminsky at one point appeared to suffer a bloody lip in the second half after a wayward ball struck him in the face.
The Boilermakers did have a few decent looks that didn't fall. They went 3 of 14 from 3-point range.
Terone Johnson provided a couple of first-half highlights with transition layups. A.J. Hammons gave Purdue hope going into the locker room at halftime after converting an offensive rebound just before the buzzer to get within 35-24.
Then Terone Johnson's layup about 30 seconds into the second half got Purdue within 38-30.
It was simply a momentary lapse for Kaminsky and the Badgers.
Kaminsky went 3 of 4 in the second half from 3-point range. It was his best shooting game from behind the arc since making six 3s on Nov. 19 against North Dakota.
Kaminsky finished 8 of 11 from the field overall.
Ronnie Johnson was 7 of 17 from the field for Purdue, while Terone Johnson finished with 12 points on 5-of-10 shooting. Hammons had 11 points and 11 rebounds.
The Boilermakers lost a third consecutive game to a ranked opponent after falling to No. 12 Michigan last week and No. 24 Iowa on Sunday.
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