MEXICO CITY - Austin Ernst shot her second straight 5-under 67 on Saturday to take the third-round lead in the Citibanamex Lorena Ochoa Invitational.
Ernst had her second straight bogey-free round at Club de Golf Mexico after opening with a 72.
''I have been hitting my driver pretty well, which I get a lot of looks at birdie,'' Ernst said. ''I have had a lot of good looks this week so even when I am not making everything, like today, I still made five birdies. So, I have just made it very easy when I haven't been sure about myself, missing greens and I haven't had many hard putts for par.''
The 24-year-old American won the 2014 Portland Classic for her lone LPGA title.
She's coming off a two-week break.
''Everything I've been working in the last two weeks is definitely turning out how I wanted, so it is nice to see it,'' Ernst said.
At 10-under 206, she had a one-stroke lead. Second-round leader Sarah Jane Smith of Australia had a 72 to drop into a tie for second with Spain's Carlota Ciganda (68).
''I was pretty nervous most of the day,'' Smith said. ''It was a position I've never been in before. I wouldn't say I handle it well, but I scrambled well, so that should give me some confidence for tomorrow.''
Ciganda won her first LPGA title last month in South Korea.
''It's tough if you come from Asia, but I was in Spain for a week just resting,'' Ciganda said. ''There is a little bit of jet lag, but I think it is better to come from Spain rather than from Asia, which is like 12 or 13 hours. I feel good, I'm looking forward to tomorrow.''
Angela Stanford, the winner of the inaugural event in 2008 at Guadalajara Country Club, had a 69 to match Karine Icher (70) and Mi Jung Hur (71) at 8 under.
Mexican amateur Maria Fassi had a 65 to get to 6 under. She's a freshman at the University of Arkansas. Gaby Lopez also was 6 under after a 73 on her home course.
Canada's Brooke Henderson, the highest-ranked player in the field at No. 7, was 4 under after a 68.
Michelle Wie was tied for 20th at 1 under after a 74. The 2009 winner in Guadalajara, she's playing on a sponsor invite after failing to qualify for the 30-player event.
Tournament host Ochoa won 27 LPGA titles. The Mexican star retired in 2010. She will be inducted into the World Golf Hall of Fame next year.