Minnesota had won 15 of its first 16 games before slumping into a three-game losing streak.
The Wildcats held Minnesota to 33 percent shooting and recorded nine steals to bounce back from an eight-point home loss to Indiana.
Reggie Hearn added 13 points and Tre Demps had 10 for Northwestern (12-8, 3-4 Big Ten Conference).
Minnesota was paced by 14 points and 16 rebounds from Trevor Mbakwe. The Gophers slipped to 15-4 for the season and to 3-3 in league play.