Stanojevic had 11 points for the Eagles (11-13, 5-7 Big Sky). Cameron Jones led the Lumberjacks (6-16, 3-8) with 11 points and five assists.
Neither team led by more than four points. The Eagles broke a five-game losing streak against the Lumberjacks.
With the score tied at 50, Valentine stole the ball, drove the length of the court and passed to Gary Gibson for a layup that put Eastern Washington up by two with 1:21 left.
In the final minute, Northern Arizona committed two turnovers and, with eight seconds left, Zarko Comagic missed a bank shot from 12 feet that would have tied the score. Eastern Washington grabbed the rebound and Stanojevic made two free throws with 3.7 seconds left.
Valentine finished with seven assists and Brandon Moore grabbed nine rebounds for Eastern Washington.