After sharing the overnight lead, Smith quickly took advantage of benign early conditions to pick up five birdies on her outward half at Shoal Creek.

It was a "strange" feeling for someone so unaccustomed to leading, and she could not maintain the torrid pace coming home, playing her final nine holes in even par. The five-under-par 67 matched her opening round.

Smith's 10-under 134 halfway total was good for a four-stroke advantage over compatriot Su Oh (68) in the morning half of the draw. Former World No.1 Ariya Jutanugarn, from Thailand, was in a share of second place with Oh at six under – through seven holes of her second round – when play was suspended for the day.

Sarah Jane Smith rolls in a birdie on her front nine of the second round. PHOTO: Getty Images.

"I was definitely nervous but not like I've been in the past. I was actually kind of happy with how I handled it a bit more today," said Smith, who is still seeking her first LPGA victory.

"I find the nerves of playing bad are a lot harder to deal with than the nerves of playing good. So I feel like it's a different nerves but they were there."

Of the other two overnight leaders, Lee Jeong-eun backtracked with a 75 to fall eight strokes back, while Jutanugarn, who had a late tee time, will have to complete her second round early on Saturday morning.

"It was weird (building a big lead). It just felt really easy. It was strange, the front nine. I was sort of holing a lot of putts. I didn't hit a great shot into 13, and then holed maybe a 40-footer for birdie there." – Sarah Jane Smith

Smith, 33, hopes to make it consecutive major winners by Australians (and Queenslanders) at Shoal Creek, following Wayne Grady's victory there at the 1990 PGA Championship.

She has a way to go, but nonetheless took delight at seeing her name atop the leaderboard the entire round.

"It's kind of fun seeing that," she said.

"It was weird (building a big lead). It just felt really easy. It was strange, the front nine. I was sort of holing a lot of putts. I didn't hit a great shot into 13, and then holed maybe a 40-footer for birdie there.

"I hit a couple squirrelly shots (late in the round), but made some nice up-and-downs. Obviously it sucked to have the three-putt on eight (her 17th), but can't complain too much."

Smith soaks in the applause from the gallery as she walks her 18th hole. PHOTO: Getty Images.

Smith, coached by one of Tiger Woods' previous instructors, Sean Foley, arrived at Shoal Creek after five missed cuts in six starts.

"Sean is in constant contact," Smith said. "So we had a really good lesson before Kingsmill (two weeks ago) and then I actually missed the cut but felt like I played really well.

"(He told me to) keep showing up, it's going to turn around. He just kind of set me straight."

US WOMEN'S OPEN LEADERBOARD

Su Oh has found some much needed form on the back of a good finish last week at the Volvik Championship. She says she was not surprised the scoring was low because players could attack the layout, softened by a rolling series of deluges during the past few days.

“We were looking at the leaderboard saying Sarah is very greedy, just taking all the birdies,” Oh laughed. “But I mean … if you hit your irons well because the course is soft, you can get access to the pins and trust that you have good numbers, it's definitely there so you can go low.

Victorian Su Oh was rock solid in shooting 68 to be just four strokes behind Smith. PHOTO: Getty Images.

“I wasn't hitting my irons like amazing but wasn't that far off, either. So, a low score is definitely out there.”

Of the other Australians in the field, last week’s winner Minjee Lee is two over through six holes of her second round and is tied for 38th place. Queensland’s Katherine Kirk is a further shot back at three over and is just inside the cut line with 11 holes left to play in her second round. Karrie Webb has a fight to make the cut, having played seven holes and is four-over-par for the championship.