Mancasola was able to gain separation early, shooting a first-round 5-under 62. The course played at a par 67 for the tournament, with the front nine playing a par 34 and the back nine playing a par 33.
Mancasola shot a final round 1-under 66 to hang onto the Championship by two shots after starting the day two shots up on Scott Bubany of Rocklin, Calif.
Mancasola recorded seven birdies, five bogeys, and two eagles, both coming in round one.
Bo Lizarraga of Camino, Calif., finished in solo fourth place at 2-under, and Jayden Lizama of Elk Grove, Calif., finished in solo fifth place at 1-under.