Hawaii (1-0) went on a 38-11 run over the first 11:30 of the second half for a 70-45 lead. Shaquille Stokes hit a pair of 3-pointers early in the surge.
Cal State Northridge (0-2) scored the next 11 points to pull to 70-56 with 5:22 remaining, but couldn't get closer than 13 the rest of the way.
Stokes added 14 points and Vander Joaquim had 12 for the Rainbow Warriors.
Hawaii shot 27 for 57 (47 percent), while Northridge was just 22 for 71 (31 percent) -- including 3 for 23 from 3-point range.
Stephan Hicks scored 22 points for the Matadors.
The game started at 11 p.m. local time as part of ESPN's College Hoops Tip-off Marathon.