MORELIA, Mexico — Defending champion Lorena Ochoa shot a 4-under 69 in windy conditions today to take a one-stroke lead over Norway's Suzann Pettersen into the final round of the LPGA Tour's Corona Championship.

Ochoa, the top-ranked Mexican star who also won the 2006 tournament at Tres Marias, had a 20-under 199 total. After opening with consecutive bogey-free 65s, she had eight birdies, two bogeys and a double bogey Saturday.

"I was aggressive, but I can't be perfect every day," Ochoa said. "I missed a couple of shots, and that's just the way golf is. I'm still happy because I'm still on the lead and the goal is to remain there. Sunday will be complicated. Nothing is going to be easy. Suzann has the desire. So do I. I have to respect her."

The fifth-ranked Pettersen followed her second-round 64 with a 67. She eagled the par-5 eighth and had four birdies, but failed to convert a short birdie chance on 18.

"Whatever happened, happened, there's nothing you can do about it. I'm happy because there are still 18 holes to play," Pettersen said. "It was a good round, not perfect. I managed to gain ground on Lorena, which was one of my goals. ... Hopefully tomorrow, I can go out and shoot as low as I can."

Na Yeon Choi (69) was third at 15 under, Wendy Ward (66), Morgan Pressel (67) and Irene Cho (68) were 14 under, and Cristie Kerr (66) and second-ranked Yani Tseng (66) were another stroke back. Michelle Wie was tied for 13th at 10 under. She shot a 72 after opening with rounds of 66 and 71.