Hosting a Northeastern State team that had won just once in March, the Griffons swept their doubleheader with 6-3 and 4-1 wins on Saturday.
Jackie Bishop (21-7) struck out 13 batters in the first game while allowing three runs on five hits.
The Griffons struck first in the opening frame thanks to Brooke Schaben's RBI single. It could have been worse for the Riverhawks with two Griffons on base, but Kat Steponovich's liner to left succumbed to a diving catch by Madison Reed
MWSU (33-15, 16-8) plated two more runs in each of the next two frames with runs driven in by Tiffany Gillaspy, Michelle Stevenson, and Bre Fleschner.
NSU scored three run in the final inning, but Bishop punched out the final batter to secure another complete game.
Gillaspy got MWSU on the board first in game two as well, but a solo home run by Megan Robinson sent the two teams into the third inning tied 1-1.
The Griffons then hung three more runs in the frame, including Taylor Anding's fifth home run of the year.
Janie Smith (12-8) gave up one run on two hits with one strikeout over seven innings.
MWSU plays their final doubleheader on Saturday against MIAA-leading Central Oklahoma.