Lorena Ochoa failed to take full advantage, and Annika Sorenstam had an even harder time.
It was 19-year-old Ji Young Oh and 39-year-old Pat Hurst who emerged with a share of the lead on a Thursday filled with surprises.
Ochoa, the top-ranked player in the womens game who has won two of the past three majors, didnt make a birdie until the 14th hole during a morning of soft greens following a watering of the course the night before.
Its just too hard to believe, you know? Beautiful conditions, said Ochoa, who rallied with three birdies on her last five holes to finish with a par 73'six strokes behind Oh and Hurst.
I didnt play aggressive enough at this time, Ochoa said, and I hit the ball a little bit bad in the middle of the round. But luckily I finished with a birdie so Im feeling good right now.
Sorenstam, playing her final Open with retirement pending at the end of the season, walked off with a 75. She made four bogeys in a six-hole stretch and signed for her highest opening round at this major since she played in 1992 as an amateur. The 37-year-old Swede sounded positive, though, as she dissected her performance.
Im hitting the ball beautifully, Sorenstam said. Maybe one shot here or there that I missed. Other than that, its on the numbers. The direction, everything, it feels very, very good. So I just got to be patient.
I know I got the game and I love the golf course just a long ways to go.
Michelle Wies road back to recovery is even longer after shooting an 81.
Hoping to build on recent momentum after a rough couple of years on tour, Wie butchered the ninth hole on her way to a quintuple-bogey 9'lightly dinging the shaft of her putter against her head in dazed frustration.
She eventually regained her composure and even resorted to some gallows humor when she climbed three steps onto a dais to take questions from reporters.
This is my execution platform, she said with a grin.
Hurst was headed that way after missing yet another short putt, but she played her next seven holes in 6-under par and finished off her round of 6-under 67 with an 8-iron that rolled off the fringe to 3 feet.
She missed the cut in her past two events, including the LPGA Championship, which she blamed on bad putting. On greens that firmed up under the afternoon sun, Hurst stubbed a chip on the 13th for bogey and followed that by missing a 4-foot par putt.
Thats when she started moaning to her caddie about a vicious cycle she couldnt shake.
I was whining, she said. I was being a golfer.
Then came a 35-foot birdie putt down the hill that disappeared into the cup, and Hurst looked up at her caddie in mock disgust.
It just turned it all around right there, she said.
Hurst birdied the 16th hole, reached the par-5 18th in two with a 3-wood for a two-putt birdie, then took advantage of consecutive par 5s on the front nine. She hit a slight fade with her 7-wood up the hill to a right hole location on the par-5 second and made a 15-foot eagle, then capped off her big run with a sand wedge to another elevated green that stopped 10 feet away.
Hurst has been around long enough to know that a name atop the Thursday leaderboard doesnt mean much. She was thrilled, though, to see her name at all after the start she had.
This week I wasnt expecting much, Hurst said. I just want to go out and play the best I can. Ive been hitting the ball really well, just not scoring. If I can keep that flat stick going, its going to be good.
Song-Hee Kim was another shot back of the co-leaders after a 68, and Louise Friberg and reigning U.S. Womens Amateur champion Maria Jose Uribe of Colombia were at 69. Laura Davies, who won the Open in 1987 and needs one more major to get into the World Golf Hall of Fame, was in a group of five at 70.
Thirty-two players broke par, the most since 43 under scores were recorded in the first round of the 1999 Womens Open at Old Waverly in Mississippi. This Donald Ross design at Interlachen has five par 5s, which helps make up for the long distance.
Oh was in the morning group and didnt have to work too hard on the greens. All seven of her birdies were inside 10 feet, and four of them were inside 2 feet.
I love hitting my drivers and short irons, Oh said. And for that, I think this golf course suits my game pretty well.
It should suit Ochoa well, too. That expectation wasnt lost on her during a day of low scores.
I was just disappointed that it was not me, she said. Because it was playing fairly easy in the morning. For sure, I could have finished 2- or 3-under par and been in a better position. But I think it will come back. The U.S. Open is always tough, and Im OK where I am.
Editor's Note: Don't miss the live U.S. Women's Open blog, as well as other championship coverage, from partner Golf for Women magazine at golfforwomen.com.