Mbakwe came off the bench to hit 5-of-6 shots from the floor and 4-of-6 from the free throw line for the Gophers (11-1), who won their seventh consecutive game.
Andre Hollins scored 11 for Minnesota and was 3-of-6 from 3-point range.
Lawrence Alexander led North Dakota State (8-3) with 19 points and six assists. Taylor Braun added 15 and Marshall Bjorklund scored 12, but the Bison could not extend their three-game winning streak.
Minnesota carved out a 37-26 lead in the first half and played the visitors virtually even in the second half. North Dakota State hit a scoreless dry spell that lasted about 4 minutes early in the half that allowed Minnesota to build a 51-32 advantage.