The Rams (2-0) trailed by nine early but rallied to take a 38-34 lead at halftime. They opened the second half on a 10-4 run to push the lead to 48-38 with 14:50 left.
Colorado State finished shooting 58.7 percent.
Denver got within 66-57 on a layup by Stafford but the Rams' Jesse Carr hit a 3-pointer and a layup to get the lead back to 14 with 3:10 left.
Denver missed several layups in the second half and struggled from the field after a hot start and shot just 44.7 percent from the field.