Katherine Kirk has fired the lowest round of her 14-year LPGA Tour career to charge to the lead at the Thornberry Creek Classic in Green Bay.
The Queenslander took just 29 strokes to carve up the back nine en route to a blistering nine-under-par 63 in Oneida, Wisconsin, leaving her three clear of the field during a second round left incomplete by dangerous weather.
The 35-year-old led after round one with a previous best eight-under round at the ISPS Handa Women's Australian Open at Royal Adelaide in February.
But until a season-best 10th in Arkansas two weeks ago, it has been relatively slim pickings in 2017 for Kirk.
And although two under through the turn, there was still no sign of the pending explosion as Kirk found the touch with her irons that has twice taken her to LPGA glory, although not since 2010.
"I've been hitting it well lately, but I just always struggle with timing or something being not quite hot when everything else is firing," Kirk said.
"I felt like I was striking it well yesterday (in an opening 68), but I just didn't capitalise.
"But today I was really happy with it."
Kirk birdied the ninth to gather momentum, but then erupted with two more on the 10th and 11th and an eagle on the par-five 14th.
Three successive birdies then followed from the 15th, including one from 1.2m on the long par-three 17th.
"I hit it to four feet … on the 17th to a tough pin – you know things are going right when you hit a little 4-hybrid into four feet," she said with trademark smile."
Kirk said her husband, Tom, paid a visit to the course earlier in the week and predicted there might be some low scores on offer.
"I'm just happy it was me," she said.
Kirk led American Jaye Marie Green by three at 13 under late in the round, delayed for about four hours by lightning in the area.
Minjee Lee was the best placed of the other Aussies, finished at three under after an even-par 72.
She was joined by Karrie Webb in a logjam at that total through 11 holes of her second round, with that figure the projected cut line.
Sarah Kemp still also has six to play, but at four over, she'll need a miracle to make the cut, a feat that will elude Sarah Jane Smith who's finished at the same score.
WATCH KIRK'S INTERVIEW: http://www.lpga.com/videos/katherine-kirk-cards-63-round-2–2017-thornberry-creek-lpga-classic