Jamal Webb added 11 points, seven rebounds and seven assists for the Green and White (13-15, 10-8 Big Sky), which maintained its hold on third place in the conference standings. Shane Benton had 10 points.
Portland State (8-17, 5-12), which had its three-game winning streak snapped, is in danger of being eliminated from the Big Sky tourney, which takes the top seven teams. The Vikings are three wins behind the seventh spot in the conference with three games remaining.
Aaron Moore led Portland State with 16 points and 15 rebounds. Michael Harthun scored 13, Lateef McMullan 12 and Renado Parker 10.
North Dakota swept the season series, also defeating the Vikings 85-76 on Jan. 19.