Dekker also snagged seven rebounds in the victory, which extended Wisconsin's (23-5, 10-5 Big Ten) winning streak to six games.
The Badgers trailed by 10 points at halftime, but took the lead for good in the fourth quarter when Dekker hit a 3-pointer with under 9 minutes to play that sparked a decisive 12-0 Wisconsin run. The Badgers led by double digits the rest of the way.
The loss spoiled a 24-point performance by Indiana's Yogi Ferrell. Noah Vonleh added 18, but the Hoosiers lost for the fourth time in five starts.