Santa Clara (5-0) remained unbeaten by hitting 51 percent of its shots and converting 17 of 21 free-throw attempts.
Raymond Cowels III scored 12 points for Santa Clara, hitting four 3-point shots.
Eastern Washington (1-5) had a 27-19 scoring advantage off the bench, but could not remain in contention.
Collin Chiverton scored 19 points, including 4-of-8 shooting from 3-point range.
Eastern Washington had a 39-29 rebounding advantage, getting a game-high eight from Justin Crogsile.