The notorious Erin Hills club may be largely devoid of trees but it was the morning winds and course's challenging contours that had the world's best players scratching their heads on Thursday (Friday AEST).
By the end, Americans Angel Yin and Yealimi Noh, South Koreans A Lim Kim and Jin Hee Im, Japan's Rio Takeda and Spaniard Julia Lopez Ramirez were in a six-way tie for the first-round lead after all fired four-under-par 68s.
No Australians managed to shoot under par at the season's second major championship, which carries a $US2.4 million ($A3.7m) winner's cheque out of the $US12million ($A18.6m) total purse.
But as Yin said, "you can't win the tournament on Thursday but you can shoot yourself out of it".
"On 17 I made like the most basic mistake, like the worst mistake you can make. It's like elementary level, terrible," Yin said. "I just needed to make it onto the green. I'm already not like in a great position. I'm trying to make par.
"Then I just made a tiny mistake. Didn't hit it as good, and it just goes all the way down. ... This is what this course can do, and it's just challenging all around."
Hannah Green appeared to be heading that way after racking up a wretched double-bogey seven at the seventh, her third-last hole of the day after teeing off on No.10.
But the world No.8 rallied with birdies at her final two holes to claw her way back to even par.
Green, Grace Kim and American world No.1 Nelly Korda were among 24 players to post rounds of 72.
Green carved out hers in the complete opposite manner to Korda, who collected her lone birdie of a frustrating day at the par-5 last.
Green mixed three bogeys and that double with five birdies, including four on the back nine to earn her way into a share of 34th spot.
Minjee Lee is one stroke further back after struggling to find her groove, even with the gallery support of the legendary Karrie Webb.
Webb is in town to mark 25 years since Australia's most prolific ever major winner went back to back at the US Open in 2000-01 and figured she'd follow Lee around.
Gabriela Ruffels also carded a one-over 73, but remains in the hunt only five shots behind the leaders.
Steph Kyriacou opened with a 74, while Jennifer Elliott has a mountain to climb to make the halfway cut on her major championship debut after starting with a six-over 78 to be tied for 132nd in the 156-player field.
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