Griffan Callahan added 16 points and Chad White scored 12 for the Jackrabbits (10-4).
Tony Wroten led Washington (5-5) with 23 points. Darnell Gant added 15 and C.J. Wilcox scored 12 points for the Huskies.
Washington used a 15-8 run to open the second half, cutting South Dakota State’s lead to 59-48 with 13:30 remaining.
But, the Jackrabbits used numerous trips to the free-throw line to broaden the lead. Brayden Carlson made two free throws with 9:15 left to expand South Dakota State’s lead to 70-52.