Trio share lead at tight LA Championship
Iwai revealed she had been in a rush to make her tee-time after her alarm clock failed to go off, but there was no sign of any fluster on the course.
She shot a bogey-free, eight-under round of 64, starting off her round with an eagle on the par-five first hole as the 22-year-old, who has six wins on the Japan Tour, put herself in contention for her first victory on the LPGA Tour.
Iwai was paired with her twin sister Chisato for the third round but said that hadn't influenced her approach to the day.