In pursuit of her first LPGA victory, she posted a 14-under 202 total with one round left, with Australian teenager Minjee Lee (68) and American Ryann O'Toole (68) equal second on 11-under.
"After I make birdie on 10, I feel better, because I miss few putts on the front nine," the long-hitting 20-year-old leader from Bangkok told reporters.
"I feel like, OK, just make more birdies ... and I did."
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There was nothing early in Jutanugarn's round to suggest it would be anything special.
After starting the day four strokes from the lead, she bogeyed the second hole, before picking up birdies at both par-fives on the front nine to turn at one-under for the day.
The back nine was nearly perfect. She compiled five straight birdies from the 10th, before suffering a mini-disaster at the 15th with a mere par.
Normal service was resumed as Jutanugarn birdied the 16th from 10 feet, before almost holing a wedge for a tap-in birdie at the par-five 17th.
She put an exclamation mark on her performance by coaxing home a five-footer at the par-four 18th, posting the best round of the day by three strokes.
Jutanugarn, whose older sister Moriya also plays on the LPGA circuit, is currently ranked 20th on the LPGA money list.
(Reporting by Andrew Both; Editing by Larry Fine)
