Leona Maguire shot an opening 66 to lie two strokes off the lead after the opening round of the CPKC Women's Open in Ontario.
The Cavan player was in a group trailing Japan's Akie Iwai, who birdied her last two holes for a seven-under-par 64.
Maguire birdied three of her first five holes, adding three more birdies after her sole dropped shot on the ninth as she hit 13 of 14 fairways.
"Really happy with the way I played," she said. "Hit a lot of fairways, which I feel is key around here as the rough is really thick."
She is joined on five-under-par by Jeeno Thitikul, Gaby Lopez, 2003 winner Megan Khang and 15-year-old Canadian amateur Aphrodite Deng.
Iwai is chasing back-to-back wins after securing her first LPGA Tour title at the Portland Classic.
