After opening with 68-74 in the first two rounds to trail second-round leader and defending champion Zach Hammond, Tolsma fired a one-over 71 on Monday to inch ahead of Anthony Perea, whose final-round 69 brought him back into contention after 78 in the second round.

Hammond's lead entering the last day was doused with a final-round 81, finishing in seventh place.

Perea was one of two players to shoot 67 in Saturday's first round, along with Paul Bradvica.

The tournament is open to amateur players who are residents in San Bernardino County or are members at clubs inside of the county line.