Dahmen led by two over fellow American Wes Homan before play was suspended due to darkness.
Dahmen said the soft, damp conditions allowed him to take aim at every flag and employ an aggressive style of play, carding 11 birdies on the day, including birdies on his final three holes.
Along with the aggressive strategy, Dahmen said a putting tip from close friend and fellow PGA Tour Canada player Will Strickler led to a solid performance on the greens in round one.
With two top-10 finishes on the year, Dahmen sits 21st on the PGA Tour Canada Order of Merit, a fact he said he is keenly aware of with two events to go.
Homan posted a bogey-free 64 to sit at 8-under par. Next on the leaderboard is Times Colonist Island Savings Open winner Stephen Gangluff, who carded a 6-under par 66.
- Johnny Bloomfield had the eighth hole-in-one of the season with an ace from 194 yards on the 15th hole with a 6-iron.
- Thursday’s first round saw the use of preferred lies, the first time the rule has been implemented on PGA Tour Canada this season.
- Yesterday’s first round was the fifth time a round has been suspended on Tour this season and the first time with a suspension due to darkness.
- Dahmen's 62 was tied for the best round on Tour this season, matching his own 62 at the Dakota Dunes Open presented by SaskTel, another 62 at the same event by Christopher DeForest and a 62 by Brandon Harkins at The Great Waterway Classic at Upper Canada Golf Course.
- Order of Merit leader Riley Wheeldon was 4-under par through 17 holes when play was suspended due to darkness.