Ochoa got off to an eagle-birdie start, but a double bogey at No. 15 spoiled her round and left the top-ranked Mexican star three strokes behind leaders Stephanie Louden, Nicole Castrale, Karin Sjodin and Reilley Rankin.
The four leaders, tied at 4-under 138, are all seeking their first LPGA Tour win.
'No matter who is up there, I know that I have played just as well as they have, and I want to win just as much as they do,' said Sjodin, a former Oklahoma State star who leads the tour in driving distance.
Rankin shot a 3-under 68, Louden had a 69, Sjodin a 70 and Castrale a 71.
'Of course it's better to have those names up there than Annika (Sorenstam) and Lorena,' Sjodin said. 'But I still think if I had played just as well as them so far, I can do it tomorrow as well.'
Rankin's 68 matched Mi Hyun Kim and Young Kim for the low round of the day on a windy, but much drier course at Cedar Ridge Country Club. Mi Hyun Kim and Angela Stanford (71) were one stroke behind the leaders. Se Ri Pak (71), Katherine Hull (69) and Virada Nirapathpongporn (70) were tied for seventh, two strokes off the lead.
Pak, who has 23 career wins, is the only player among the top nine that has more than one career victory. Stanford is the only other with even one win, and it came at the 2003 ShopRite LPGA Classic.
Seven players were three strokes back, including Juli Inkster (70) and Ochoa (71), who took over the No. 1 ranking from Sorenstam last week.
Ochoa had birdie putts at the fourth and fifth holes slide just past the right edge of the cup, and her round soon took a turn for the worse. The wind caught her tee shot at No. 6 and dropped it on the far side of the green. She three-putted for bogey to fall to 2 under.
Ochoa ripped a drive well beyond 300 yards to straighten out a dogleg right and set up a birdie at the 399-yard par-4 seventh. She had another birdie at No. 10, and bogeys at the eighth and 13th holes before misjudging the wind at the 185-yard 15th.
'I hit it the way I wanted to hit it. I hit it so low that the wind didn't even touch the ball. I ended up on the back of the green,' the Mexican star said.
'Sometimes it's just a learning experience. It would be different if you miss a shot and end up in the water or hit a tree or something. I hit the perfect shot, but just ended up in a bad spot. I will learn from that and not do it again.'
A day earlier, Ochoa said she hoped to perhaps play a low round on Cinco de Mayo 'for my Mexicans.' She wore a light green polo shirt and sweater and white shorts, and she appeared poised to take over the tournament after she reached the green on the 520-yard, par-5 opening hole in two shots. She then knocked down a 30-footer for eagle with her putter featuring a green, white and red grip.
She drilled her tee shot within 5 feet on the next hole, then curved in her birdie putt. That ended up being the high point of her day.
'Obviously, I'm not very happy with that double bogey on the par 3. It doesn't feel good. The good thing is that I'm only three shots behind the leaders, and I'm feeling good with my game,' Ochoa said. 'I think I hit the ball very solid today, gave myself a lot of birdie opportunities.'
To earn her first win as the world No. 1, she'll have to make up ground.
Castrale, the first-round leader, holed out a 6-iron for eagle at No. 4 for her second chip-in of the tournament. She pitched in on the third hole Friday.
'There are a lot of great players on the leaderboard, whether they've won or not,' said Castrale, who played in college at Southern California.
Louden, who birdied the first two holes, held the lead for a time after two more birdies at the ninth and 11th holes got her to 6 under. She had bogeys at Nos. 13 and 16.
Rankin was the last of the leaders on the course and had a chance to take the outright lead, but had a long birdie putt skate just right of the hole. Her knees buckled after watching the putt roll past the hole.
Still, being atop the leaderboard capped a yearlong struggle to regain her form.
'I call it Reilley's world. It doesn't matter how I do it. I just do it,' said Rankin, who's never finished higher than fourth at a tour event. 'And I don't have to know or be able to explain it to somebody.
'That's what makes me good is to just play like that. I have to play my way.'
Defending champion Cristie Kerr, who set the course record with a 61 in the second round last year, missed the cut after shooting a 77.