Owen held the lead and a share of the course record after overcoming a nightmare start but an hour later Piercy's best of 62 at the Hamilton G&CC put him in charge.
"In all honesty I didn't feel like I had a very good feel for the golf course teeing up on the first hole today [Thursday]," Piercy said.
"I flew in late on Tuesday, played the pro-am so I'm kind of jet lagged playing, and kind of scraped through yesterday [Wednesday]."
Piercy made five birdies, two eagles and just one bogey in the opening round, closing in 30.
Owen, who started his round on the back nine, dropped three shots in his opening two holes with a double-bogey on the par-four 10th followed by a bogey five on the 11th.
But he recovered to hit six birdies in his next nine holes and then an eagle three at the par-five fourth and another birdie at the fifth lifted him to six under. He went on to pick up another shot before completing his round.
But that was before Piercy came to the front with his course best round of 62.
Piercy finished the day on eight under, one shot ahead of Owen and American William McGirt. Robert Garrigus sat alone on six under.
Open champion Ernie Els finished on two over.