FIRST ROUND LEADERBOARD:
-6 J-Y Oh (Kor), P Hurst (US) -5 S-H Kim (Kor) -4 MJ Uribe (Col, am), L Friberg (Swe), J-Y Shin (Kor) -3 C Matthew (Sco), L Davies (Eng), H Alfredsson (Swe), P Creamer (US), L Wessberg (Swe)
Selected others: Level L Ochoa (Mex) +1 K Stupples (Eng)
+2 A Sorenstam (Swe) +5 J Moodie (Sco) +8 M Wie (US)
Oh is playing in her second year on the LPGA Tour
South Korea's Ji-Young Oh and American Pat Hurst fired six-under 67s to share the lead after the first round of the US Women's Open in Minnesota.
The duo were one shot clear of Song-Hee Kim, with Colombian amateur Maria Jose Uribe, Swede Louise Friberg and Ji-Yai Shin one stroke further back.
Scotland's Catriona Matthew and England's Laura Davies were in a group on three under.
World number one Lorena Ochoa carded 73 and Annika Sorenstam took 75.
Oh, one of 32 South Koreans in the field, rolled in six birdies in her first 12 holes on the 6,789-yard Interlachen course, the longest in the championship's history.
"I think this course suits my game pretty well, so I'm pretty confident this week," said Oh, who turns 20 next month. "I made seven birdies today and the longest was maybe 12 feet."
American Michelle Wie was near the bottom of the pile after amassing an 81 that included a quintuple bogey at the par-four 9th, where she took six strokes to hole out from over the back of the green.
Davies, who won the title back in 1987 and is playing in her 23rd successive US Open, is bidding for a fifth major which would earn her a place in the LPGA Hall of Fame.
"I played here in the Solheim Cup (in 2002) and I've been saying ever since they announced the venue that I was really looking forward to playing a US Open at Interlachen," said the 44-year-old veteran.
"The course gives me a bit of freedom, and I can hit a few more drivers. I hit seven today.
"I have been playing well recently without being able to string four good rounds together, but this would be a great week to do it."
Former world number one Davies admitted that the mental side has changed more than her hitting of the ball.
"My head's not quite as good as it used to be," she said. "I tend to see more negative stuff than I used to."
Karen Stupples, the leading British player on the LPGA Tour this year, had one birdie and two bogeys in a one-over-par 74.
But it was a disappointing opening round for the fourth British player, Scotland's Janice Moodie, who had a couple of birdies but also had seven bogeys in a 78.