More than 150mm of rain that soaked the Shoal Creek course between Sunday and Wednesday prevented many players, including Smith, from getting in even one full practice round.

But Smith prevailed to share the lead at five-under 67, good for a two-shot first round lead over a group including 2014 champion Michelle Wie.

Smith, who had only nine holes' practice, was almost giddy with delight at her lofty position.

"I've never had the lead. I would much rather be playing well than not," said the 33-year-old journeywoman, who eagled the par-5 11th from 87 yards.

Although the course was damp and downright soggy in places, it didn’t bother Thailand's Ariya Jutanugarn, who eschewed her driver in favour of a 3-wood off the tee.

The tactic paid off handsomely as she largely avoided the soggy rough and took advantage of soft greens to fire approach shots to within birdie range with monotonous regularity.

Smith signs an autograph for a young fan following the first round of the 2018 U.S. Women's Open at Shoal Creek. PHOTO: Christian Petersen/Getty Images.

An eagle at her 15th hole, the par-5 6th, where she hoisted a five-iron to five feet, capped off a near perfect morning.

"My game was pretty good today," said Jutanugarn, who arrived in sizzling form after winning the Kingsmill Championship.

Her practice was affected not only by the wet but by her clubs getting lost in transition.

"It's tough for me today because I didn't see the front (nine)," said Jutanugarn, 22, who became the first Thai player to win a major title when she captured the 2016 Women's British Open.

Players expressed surprise at how much it dried out in the 24-hour window of dry weather before the first round.

"It's mind blowing how great the golf course is," Wie said after a 69.