Irishwoman Maguire made six birdies and an eagle in her bogey-free round at Blythefield on Sunday to finish at 21-under. She caught playing partner Ariya Jutanugarn with an eagle on the par-5 14th hole to reach 18-under, then closed with three straight birdies to pull ahead of the Thai and China's Xiyu Lin.

"I've been playing some really good golf leading into this week, and just tried to be patient," Maguire said.

"It was nice to go bogey-free on Sunday and my goal today was to get to 20-under. Nice to go one better than that."

Minjee Lee (72) was the best-placed Australian in a tie for 13th at 13-under with compatriots Grace Kim (65) finishing 11-under, Hannah Green (66) six-under and Steph Kyriacou (74) one-under.

Maguire was solid but unspectacular on the front nine, birdieing both par-3s, and was two-under for the day through 12 holes. She then birdied the par-3 13th to kick off her torrid closing stretch.

Jutanugarn, a 12-time winner on Tour including two majors, shot her second straight 66 and finished alone in second. Lin, playing in the final group, birdied the 14th to reach 19-under but played her final four holes in one-over to shoot 68 and finish tied for third with third-round leader Amy Yang (69) of South Korea.

The 28-year-old Maguire was the runner-up at Blythefield in both 2021 and last year. She won her first LPGA Tour title last year at the Drive On Championship. Sunday's finish was her third straight in the top-10 heading into two upcoming majors: the KPMG Women's PGA Championship next week and the U.S Women's Open at Pebble Beach on July 6-9.

"I felt like I played some really good golf last year. Missed out in a play-off here, second at CME. You have to play really good golf to win out here. It's tough," Maguire said.

"It's a really nice feeling to get this one, and especially heading into the majors we have coming up."

Defending champion Jennifer Kupcho of the United States had a fourth-round 69 and finished in a tie for sixth with another Jasmine Suwannapura (66).