Navy is now 7-3.
Oregon was led in scoring by Dillon Brooks with 19 points. Dwayne Benjamin had 16 while Chris Boucher had 14 points (in addition to 14 rebounds and three blocks) while Casey Benson added 10.
Navy was led by Will Kelly with 13 points followed by Jace Hogan with 10.
Oregon shot 47.1 percent from the field on 24-25 shooting including 6-15 in 3-point shooting and was 13-16 in free throws. Navy shot 31.6 percent on 18-57 from the field including 2-14 in 3-pointers and 9-18 in free throws.
The Ducks held a 36-35 rebounding edge and had 14 steals.
Oregon will face Boise State on Saturday at Boise with tipoff scheduled for 4 p.m. Pacific in a game that will be carried on CBS.