First-round leaders hardly ever win this event, and a playoff rarely is required. In this case, none of the top five finishers stood in the top five after Saturday's round. Gentry Hicks (73-66) and BYU golfer Justin Keiley (72-67) tied for third place, while Robert McRae (70-70), Dan Horner (71-69) and BYU's Cole Ogden (71-69) tied for fifth.
Jordan Bloxham, who opened with a 68, posted a final-round 75 and tied for ninth.
Troy Creer (76-74) won the A flight and Terry Treseder (76-87) and Donald Wallace (80-83) tied for first in the B flight.
Parkinson, the 2010 State Am champion and low amateur in last summer's Utah Open, eagled the par-5 No. 1 and made four other birdies during an exceptional ball-striking round. The Alpine product made no putt no longer than 8 feet.
Being behind didn't necessarily factor into Parkinson's approach Sunday. "I've just always been an aggressive player," he said.
For the weekend, Parkinson played Bonneville's four par-5s in 8 under par, with two eagles.
Parkinson produced a strong sophomore year for BYU with a victory and four other top-five finishes, although he was disappointed when the Cougars barely missed qualifying for the NCAA Championship. He's embarking on an ambitious national amateur schedule this summer, intending to make the Utah Open his next in-state appearance in late August at Provo's Riverside Country Club.