Portland opened the game with an 8-0 run and led 28-11 midway through the first period and 46-28 at intermission.
Gerun was 10 of 12 from the field and knocked down a 3-pointer to lead the Pilots (3-0). Kevin Bailey added 12 points and the Pilots shot a collective 47.7 percent from the floor (31 of 65).
The Cougars were led by Keaton Jackson and C.J. Carr, who scored 13 and 10 points, respectively. SIU-Edwardsville was 22 of 56 from the field (39.3 percent) and converted just 4 of 19 shots from long range.
Portland had a substantial edge on the boards, 44-28, and held a 17-7 edge in points off turnovers. The Pilots also had 18 second-chance points.