The Royals used a 13-0 run in the second quarter to break open a close game.
Mason County outscored Augusta 23-8 in the second quarter to lead 41-22
The Royals led by as many as 26 points in the fourth quarter.
Dunaway hit 19-of-23 free throws. He moved into 10th place on the Royals' all-time scoring list.
Malkolm Devine scored 15 points and Jaylen Lofton added 14 points.
Augusta senior Thomas Mains scored 17 of his team-high 21 points in the fourth quarter.
Mason County snapped a three-game losing streak and advanced to the championship game Thursday night.
MC (16-13) Dunaway 38, Lofton 14, Frey 4, Jones 5, Devine 15, Brammer 4, May 2
A (12-15) Eichenberger 10, Ripato 12, Philpot 5, Appelman 6, Cordle 4, Mains 21, White 3
MC 18 23 12 29- 82
A 14 08 10 29- 61
