Touchdown runs from Alex Shoop, Leroy Quinn, and Masterman in the first quarter helped the Eagles jump out to an early 21-0 lead.
In the second quarter, Masterman added four scores, three on the ground and one through the air, while Shoop also added a score, giving Oakridge a 55-0 halftime lead.
Robert Rivord finished off the Eagles scoring with a 5-yard run in the fourth.
Mason County Central found the end-zone on a 31-yard rush from Bruce Banks in the third.
Quinn finished with 153 yards on 11 carries for the Eagles while Masterman totaled 118 yards on six rushes.
Rivord led the defense with six tackles for Oakridge, which improves to 5-1 on the season, 4-1 in conference.