"It was a great day," Ochoa said. "No bogeys. I enjoyed that very much."
South Korea's Inbee Park was second after a 9-under 64 that tied the course record set by Ochoa in 2006 and 2007.
Park was excited about playing alongside the top-ranked Mexican star on Saturday.
"I've always wanted to, but never got a chance to because she always plays in the last group and I never do," said Park, who had 10 birdies Friday,
Ochoa, the Kraft Nabisco Championship winner Sunday for her second straight major victory and third win in three starts this year, said she liked the close competition because it pushed her to focus.
"It makes me more aggressive and try to catch up, but either way, tomorrow I'm going to play like I'm three or four shots behind and try to win the tournament," the 20-time LPGA Tour winner said.
If the 26-year-old Ochoa wins Sunday, she will earn the last of the 27 points needed to qualify for the Hall of Fame. The youngest to qualify previously was Se Ri Pak, who was 26 years when she won the Michelob Ultra Open in 2004.
The LPGA Tour awards one point for every victory and major award and two points for a major victory. Ochoa still must play 10 years on the LPGA Tour before she becomes eligible for the Hall of Fame, a goal she would reach in the 2012 season.
A victory Sunday also would also be her second at the rugged Tres Marias, a steep and often rocky course carved into a mountain valley in western Mexico. She was the Corona champion in 2006, her only tournament win on Mexican soil.
On Thursday, Ochoa eagled two par 5s in a 66 to tie for the lead with South Korea's Song-Hee Kim. On Friday, Ochoa eagled the par-5 10th.
