Jack Lopez nailed a 3-pointer from the corner to pull Montana to 61-58 and then Brandon Gfeller had a steal and fast-break layup to make it 61-60. After another North Dakota turnover, Breunig hit a shot in the lane for a 62-61 lead.
Breunig made a hook shot for a three-point advantage and the Grizzlies forced a missed shot on the other end, but they turned it over under the basket. Quinton Hooker missed a reverse layup and Breunig sealed it with one free throw.
Breunig had 27 points and 12 rebounds for Montana (11-6, 6-0 Big Sky).
North Dakota (8-9, 3-3) was paced by Hooker with 20 points.
Conner Avants made two 3-pointers during North Dakota's 17-4 spurt for a 49-42 lead. He made two free throws during the run for its first lead since 23-22.