Now Ochoa is looking to start a streak of her own.
'My goal is to maintain that position to be No. 1,' the 25-year-old Mexican said. 'I can only tell you it's going to be a big challenge.'
Ochoa and Sorenstam are among the players to watch in the Safeway International, which begins Thursday at Superstition Mountain Golf and Country Club on the eastern outskirts of Phoenix. Nestled in the foothills, the course is about 100 miles north of the University of Arizona, where both women had standout careers.
They've collided here before, with dramatic results. In 2005, Ochoa blew a four-stroke lead with three holes to play and lost a playoff to Sorenstam.
Both have played well on Superstition Mountain's Prospector Course, the site of the tournament the last three years. Ochoa tied for third in 2004, finished second in 2005 and tied for 24th a year ago. Sorenstam won in 2004 and 2005 and tied for 19th last year.
But while their competition appears to be an obvious storyline, Ochoa downplayed the potential rivalry with Sorenstam.
'It's not about Annika, about one player,' Ochoa said.
Still, the 36-year-old Sorenstam remains No. 1 in the world rankings and is the prime target on an increasingly competitive tour.
'Last time I looked, she was still ranked No. 1 in the world,' said Hall of Famer Juli Inkster, the tournament's defending champion. 'So I think she's always the person to beat.
'If I was a betting person, and Annika was in the field, I'd probably take her every week and probably make out pretty good at the end of the year.'
Last year, Ochoa was often the best bet. She won six tournaments and earned $2,592,872, becoming only the second player, after Sorenstam, to surpass $2 million in a single season. Karrie Webb became the third later in the year.
Ochoa's scoring average, 69.24, was the fourth-lowest in LPGA Tour history.
'I will remember that year for the rest of my life,' Ochoa said. 'And I've been dreaming for so long to be No. 1.'
For her part, Sorenstam would just as soon forget the whole year. Although she won her third U.S. Open title and finished third on the money list at $1,971,741. Sorenstam's three victories were her fewest in a season since 1999, when she won twice.
'I was quite frustrated with the way I was playing last year,' Sorenstam said after her practice round Wednesday. 'I tried so hard and I really tried to make it work. I scrambled in a lot of events just to hit fairways and hit greens. It was tough.'
Sorenstam said she spent the winter trying to 'find my swing again.' If her last tournament was any indication, she may have found it. Sorenstam lost a playoff to Meaghan Francella in the MasterCard Classic in Mexico, and she came away happy about everything but the outcome in her season debut.
'I feel like my game is as good as I can ask it to be,' Sorenstam said. 'I felt like my swing is back. The distance is back. The accuracy is also back.'
Both Ochoa and Sorenstam hope a good performance here will give them a boost heading into next week's Kraft Nabisco Championship, the first major of the season.
With 10 major victories, Sorenstam is tied with Babe Zaharias for fourth on the career list. Patty Berg holds the record with 15.
'I'm aware of the record, but I never felt like I would compare myself to the other players,' Sorenstam said. 'I've always tried to play the best I can. It would be nice to do it. I think it's possible. That's not really what drives me.'