Stupples shot a 4-under 68 to finish at 15-under-par 273, followed by Kylie Pratt (65) and Jennifer Rosales (68). That pair finished the tournament at 11-under-par 277.
Sorenstam began Sunday's final round with a one-shot lead over Stupples but extended quickly. Sorenstam birdied the first while Stupples made bogey so the margin was three.
At the par-5 third hole, Sorenstam drained a 25-foot eagle putt to put the tournament out of reach. She added four more birdies and did not make bogey to pick up the victory.
'I'm glad I got off to a hot start,' said Sorenstam.'It's so sweet to win again. The eagle at the third was definitely a key moment and after that, I kept the momentum going on the front nine and played much better on the back nine. I never put myself in any trouble, so I guess my plan came true for me.'
Stupples played well but could not overcome Sorenstam.
'Annika played supremely well today,' admitted Stupples. 'I'm very happy with the way I played over the weekend but I got to the stage this afternoon where I was thinking 'what do I have to do?' I really wanted to win this tournament, but Annika got off to a great start and I didn't.'
Anne-Marie Knight (72) took fifth at 10-under-par 278, followed by Ana Larranta, who carded a final-round, 6-under 66 to finish at 9-under-par 279.