American Lexi Thompson picked up five shots inside her first seven holes as a round of 65 saw her lead the LPGA Tour season finale.
She reached the turn on four under after a bogey on the ninth, but picked up three more on her way to a round of seven under and a one-shot lead at the CME Group Tour Championship in Florida.
Nanna Koerstz Madsen of Denmark leads the chasing pack after shooting a clean round of 66, including three consecutive birdies towards the end of her effort, while three players are tied for third on five under: Sei Young Kim, Caroline Masson and Megan Khang.
Northern Ireland’s Stephanie Meadow is tied for 16th on two under after shrugging off two early bogeys in her first four holes to complete the rest of her round flawlessly.
Cavan woman Leona is in joint-49th at the no-cut event. Maguire also struggled early on, double-bogeying the fourth to go three over but didn't hit another bogey after that as she finished on +1.
