Play is split over the par-72 layout at Raven Golf Club and the par-71 Georgian Bay Club for the first two rounds. Reifers established a new course record at Raven Golf Club on Thursday.
Roger Tambellini shot an 8-under 64 at Raven for second place. Craig Bowden and J.J. Killeen managed 7-under 65s at Raven, while Jason Enloe carded a 7-under 64 at Georgian Bay to share third place.
Reifers parred his first three holes and broke into red figures at the par-5 fourth. He reached the green in two with a 6-iron and two-putted from 15 feet.
He sank a 13-foot birdie putt at five and a 4-foot eagle putt at the par-5 sixth. Reifers converted three birdie putts in a row from the seventh with the longest coming from 18 feet at the seventh.
Reifers collected his second eagle of the round at the par-5 10th. He hit a 5-iron to 7 feet and made the putt, then holed a 25-foot birdie putt at 11.
That birdie at the 11th meant Reifers went 10 under par through Nos. 4-11.
'I'm the type of person that thrives on going really low,' said Reifers. 'The way I see it, it's all positive, there's nothing to be fearful of. Once I get it going out there, I just want to see how low I can go.'
Reifers' run ended with a thud at 12. He three-putted for a bogey, but back- to-back birdies at 16 and 17 gave Reifers the first-round lead.
'I didn't get ahead of myself out there,' said Reifers. 'Obviously if you have that many circles on the card things are going well, I just focus on trusting what I have going on. I knew I was swinging it well so I kept thinking about where I was going to put my next shot.'