Montana State (12-12, 7-6 Big Sky) went on a 15-3 run in the first half to take a 27-15 lead and was up by as many as 20 in the second, mounting a 48-28 advantage with less than 15 minutes to play.
North Dakota (10-13, 7-6) then went on a 24-7 run to pull within 55-52 with 8:01 remaining. North Dakota trailed 67-63 with 1:38 left but Montana State hit 11 of 12 free throws in the final minute to seal the victory.
Eric Norman, Stephan Holm and Paul Egwuonwu each added 10 points for Montana State, which shot 52.4 percent from the field.
Aaron Anderson led North Dakota with 20 points while Troy Huff added 17 points and 10 rebounds.