Ochoa, who teed off three hours after Pettersen in the opening round of the season’s first major, had chances to tie the Norwegian star but rolled a long putt just right of the hole on No. 17 and then missed a 10-footer on 18.
Pettersen, trying to bounce back from a hip injury, had a great start by hitting 12 fairways and 13 greens in regulation. Top-ranked Ochoa, the 2008 champion, had six birdies and two bogeys.
Majors champions Karrie Webb, Yani Tseng and Karen Stupples were in a group at 69.
Defending champion Brittany Lincicome curled in a birdie putt on 12 to drop to 4 under before bogeying Nos. 13 and 15 to finish with a 70.
Michelle Wie had a 71.
Pettersen has two top-10 finishes in three starts this year but also is coming off a hip injury that required a cortisone shot and kept her from swinging a club for about three weeks.
“I thought I was going to have two solid weeks of practice. It turned out to be two solid weeks on the couch,” said Pettersen, who won the 2007 LPGA Championship and has three straight top-5 finishes here.
Pettersen drove well, which is crucial at Mission Hills.
“It’s quite demanding off the tees, and there’s just certain tee shots you’ve just got to take on,” she said. “And I think if you can place it off the tee, I think you’re in a very good position. You’ve just got to play what this course gives you. I’ve learned that over the years. And patience, obviously. I would take a bogey-free round any day around this place.”
Asked if the greens or rough looked more difficult this year, she said: “I can’t really answer you about the rough.”
Pettersen teed off shortly after 9 on a chilly morning.
“It got really cold as we warmed up,” she said. “I thought I was going to ski, the way I was dressed.”
It warmed up by late morning and turned into a pleasant day in the desert.
Tseng, who won the 2008 LPGA Championship, had an adventuresome round including an eagle, five birdies and four bogeys.