The loss dropped the Demons to 12-17 overall and 9-6 in conference play and were swept for the first time in league action since last April 8-10 against Nicholls State.
Sam Houston State (23-9, 13-2) widened its lead in the league standings to four games over the second place Demons as it won for the 13th straight time.
The Demons scattered seven hits offensively with two of those coming in the first inning when Jordan Buckley got on with a one-out single up the middle and scored when Colin Bear knocked him in off a double to right-center field. NSU had the chance to get more in the frame with runners on second and third with one out, but two strikeouts split by a walk ended the early rally.
NSU left six runners on base for the game, four of those in scoring position.
SHSU took the lead for good with a three-run third inning behind RBI singles from Luke Plucheck, Anthony Azar and Jake Arrington off of Demon starting pitcher Andrew Adams.
Adams (1-3) took the loss after he lasted just 2.2 innings and gave up three runs on five hits with three walks and three strikeouts. He also threw two wild pitches, both coming in the third inning.
The lead increased to 5-1 in the fifth inning after Plumlee got a two-run single to left field to score Miller and Arrington who led off the frame with back-to-back singles off of Demon reliever Jamie Bittle.
NSU got two runs back in the seventh when Matt Burns got a one-out double, went to third on a grounder by Nick Doughty, and scored off a single by Drew Helenihi. Buckley blasted a triple to left field to score Helenihi and make it 5-3 but he would stay stranded at third when Nick Purdy grounded out to second base to end the inning.
The Demons never threatened in the eighth or ninth innings as Bearkat reliever Michael Oros picked up his second save on the season after he threw two scoreless innings, allowed one hit and struckout three batters.
Starting pitcher Justin Jackson (6-2) got the win after seven innings of work. He gave up all three Demon runs on six hits, walked three and struckout eight.
Buckley led NSU at the plate with a 2-for-4 showing with a RBI and a run scored and for the Bearkats, four players finished with two hits each to pace the 10-hit attack.
The Demons will be back in action on Tuesday when they visit Grambling at 6 p.m.
NSU's next home action will be next Friday-Sunday when it hosts Texas A&M-Corpus Christi in a Southland series.