The victory -- the 58th of Sorenstam's LPGA Tour career -- was her second in two events this year and sixth in her last eight tournaments.
Sorenstam finished with a 2-under 70 to match Ochoa (74) at 11-under 277.
Sorenstam, the four-time LPGA player of the year and scoring record-setter, won her season debut in Mexico City two weeks ago, dashing the 23-year-old Ochoa's dream of a victory in her native land. It was more of the same this time, but with a twist.
Ochoa was 14 under to Sorenstam's 10 under after birdieing the 15th hole.
But it was a train wreck after that for the rising Mexican star, who won twice last year and had 16 other top-10 finishes, winding up third on the money list behind Sorenstam and Grace Park.
Ochoa double-bogeyed the 16th hole for the second time in two days and two-putted from 7 feet for a bogey on the 17th.
Sorenstam reached the green on the par-5 18th in two, missed a 35-foot eagle putt but tapped in for the birdie that sent both players back to the 18th tee for the playoff.
The unnerved Ochoa put her tee shot in a long, narrow lake on the Prospector Course's only water hole, and the conclusion never in doubt from there. Sorenstam was pin-high with her second shot again, chipped 7 feet past and made the par putt.
Ochoa didn't even putt for bogey after her attempt to save par with a chip from short grass left of the cup went 5 feet past.
Juli Inkster (72) and Soo-Yun Kang (76) tied for third at 8 under.