Clarence Trent had 11 points and nine rebounds for the Redhawks (3-3) and Deshaun Sunderhaus added 10 points.
Seattle shot 50 percent from the field 59 percent in the second half. The Redhawks were ahead 33-30 and led throughout the second half, though never by more than 12 points.
The Redhawks held on despite making just 8 of 17 from the free-throw line.
Justin Crosgile led the Eagles (2-7) with 15 points. Venky Jois had 14 points and 12 rebounds and Parker Kelly also scored 14 points for Eastern Washington.