Tiegbe Bamba added 17 points and nine rebounds for Portland State (13-11, 7-7 Big Sky).
Neither team shot the ball well, each finishing below 45 percent. But Portland State got to the free throw line 28 times, its second highest mark of the season, and hit 25, also its second highest of total of the year.
The Vikings held a 15 point lead midway through the second half, but North Dakota (8-17, 4-10) battled back, cutting the lead to just one on a jumper by Josiah Coleman jumpers with 7:21 left. Portland State quickly regained control, however, pushing the lead back to 10 with 1:34 left via a 19-10 scoring stretch.
Quinton Hooker led North Dakota with 17 points and six assists.