With a 44-36 lead at the half, Colorado State (5-0) broke the game open with a 26-10 run to put the game out of reach for Portland (3-3).
Tiel Daniels had 12 points for the Rams and John Gillon added 11. Colorado State shot 31 for 58 from the floor (53.4 percent).
Colorado State raced to a 7-0 lead and then 15-15 before Portland went on a 10-0 run to tie it again.
Alec Wintering and D'Marques Tyson each had 14 points for Portland.
The Pilots made just 25 of 70 shots (36 percent) and were outrebounded 43-33. Colorado State shot 53 percent, 31 for 58.