Motum gave the Cougars (1-1) their first lead of the night when he hit a put-back with 17:35 to play. The Hornets (2-1) hung around for the next five minutes before getting into foul trouble and allowing Washington State to take control.
The Cougars took the lead for good, 51-49, on an Aden jumper with just over 12 minutes left.
Sacramento State scored the game's first seven points, and led 25-12 in the first half and 39-33 at halftime, behind the hot shooting of John Dickson, who led the Hornets with 21 points.
Washington State came alive in the second half, with Motum scoring 16 of his 23 points. He tied the game for the first time with a 3-pointer just after halftime.