The 24-year-old star from Guadalajara, seeking her fourth victory of the season, had a 16-under 203 total. She stayed consistent, hitting straight drives and safe approaches that kept her out of trouble on the hilly Tres Marias course.
Paraguay's Julieta Granada (66) was second at 13 under. First-round leader Brandie Burton (67) was 9 under, and Christina Kim (65) and Young Jo (69) were another stroke back. Wendy Ward (71) and 18-year-old Morgan Pressel (71) were 7 under.
The third round did not feature the same fireworks for Ochoa as Friday, when she shot a course-record 64 to move atop the leaderboard. Still, she got aggressive at times, recording an eagle on the 466-yard, par-5 10th. She also converted five birdies to offset a pair of bogeys.
Ochoa's success Friday swelled the crowds following her from hole-to-hole to more than 600 a day later. Every long putt she made was greeted by whoops and whistles, chants of 'Let's Go Lorena!' and even a couple of marriage proposals. Many fans wore red caps embroidered with Ochoa's 'L' logo.
The former University of Arizona player was a non-factor at last year's inaugural Corona Morelia Championship and at the LPGA Tour's MasterCard Classic played outside Mexico City in March 2005 and 2006. She faltered under pressure, seemingly pressing too hard to impress droves fans, who hung on her every swing.
But a solid day Sunday should dispel forever questions about Ochoa's struggles south of the border, where her success has made golf front-page news -- even in a soccer-obsessed nation. Charming and colonial Morelia is 175 miles from Guadalajara and dozens of Ochoa's friends and family members were among those who followed her round.
Ochoa leads the LPGA Tour in earnings with $1,974,122 and if she wins or comes close in Morelia -- the purse is $1 million, with $150,000 going to the winner -- she will top $2 million for the season, becoming just the second player to do so after world No. 1 Annika Sorenstam.
Sorenstam, who did not travel to Morelia, has led the money list every year since 2001, but is third behind Ochoa and Karrie Webb this season.
Many in the crowd also supported the Spanish-speaking Granada, cheering when she birdied or holed long putts to save par. The 19-year-old, who is seeking her first LPGA Tour victory, has a smaller, lighter bag than most players and uses her mother, Rosa, as her caddie.
Granada, who has said she considers Ochoa a kind of older sister on the LPGA Tour, also had an eagle on No. 10 and had three straight birdies on Nos. 15 to 17. She made a bogey on 345-yard, par-4 11th for the third straight day, however.
'Lorena's a great player, but you have to go out and play golf and try to win,' she said. 'I think the fans are going to be split pretty evenly between us.'
Granada said she will feel pressure being so close to her first victory, but that Ochoa will likely be nervous while trying to close out a win in her country.
'Both us are going to be a little bit nervous,' she said.
Kim had the day's best round at 8 under, hitting a 5-wood from 215 yards to 4 feet from the hole for an eagle on par-5 eighth, then reaching the green with her 4-iron from 208 yards out and sinking a 16-foot putt for another eagle on No. 10. She also had five birdies, but missed a 4-foot putt for par on No. 4.
But she said was already planning to celebrate a win here with her friend Ochoa, saying, 'I may spray her with some champagne.'
'I think they say they've got some good discos in town so, if she's willing to go, I'd like to go,' Kim said. 'I would mean a lot to me if Lorena won here in Mexico.'