The 26-year-old Spaniard shot a 4-under 68 at Club de Golf Mexico for a two-stroke victory over six players. She played the four par-5 holes in 5 under, making an eagle on No. 2 and birdies on 6, 11 and 17.
Ciganda won the LPGA KEB-Hana Bank Championship a month ago in South Korea for her first tour title. The former Arizona State player has five straight top-10 finishes.
''I am very happy to be here and to get my second victory,'' Ciganda said. ''It's wonderful to play here in Mexico. I honestly don't have any words. I love the golf course, the people, it's an honor to be here. I've been playing really good all year long and to end this year with these two victories gives me a lot of confidence, I am very happy.''
Ciganda won a year after finishing second to Inbee Park on the tree-lined course.
''Last year, I was close,'' Ciganda said. ''It was a shame not being able to win but it was still a good last day, so I had really good memories. Last week, I was back home just resting because I wanted to play here and to do so well, so I am really happy and thrilled that I was able to win.''
Her parents watched her win after missing her victory in South Korea.
''I am just very happy that they are both here and it is very special because they are great people,'' Ciganda said. ''They always tell me to have fun, they always give me a lot of calm, so I want to thank them.''
''Right now, disappointed. I just didn't play well enough today to get it done,'' Ernst said. ''Carlota played really good, especially early. I am just kind of frustrated with how I finished.''
Stanford won the 2008 event in Guadalajara.
''It was a good day,'' Stanford said. ''It's hard to shoot 3 under on Sunday and be upset, but I had two three-putts. The one on 11 would probably haunt me for a while, but I hit the ball really well and gave myself a lot of chances and I was never in a really bad spot, so to be in contention and have a day like that is pretty encouraging.''
Mexican amateur Maria Fassi closed with a 73 to tie for 15th at 5 under. She's a freshman at the University of Arkansas. Gaby Lopez also was 5 under after a 73 on her home course.
Canada's Brooke Henderson, the highest-ranked player in the field at No. 7, was 20th at 4 under after a 71. Michelle Wie (72) was 24th at 1 under after a 72. The 2009 winner in Guadalajara, she played 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.