The Swede was one under par for the day and minus seven in total when she pointed up on the seventh hole.
When she dug out of hole nine, she could look back on two bogeys and a double bogey and that the fifth place was changed to a more anonymous position.
The 28-year-old managed to keep the game together for the rest of the day, but a total of -3 for the competition was only enough for a shared 26th place.
At the top, nothing could stop Inbee Park.
The South Korean's one under par was far from today's best score, but quite enough to hold off and win by six strokes ahead of the American duo Amy Olson and Lexi Thompson.
The two were in turn six strokes ahead of Sagström.
Anna Nordqvist went around on a stroke over par and finished 33rd.
Pernilla Lindberg was clearly the best of the three Swedes who play on Sunday, but after problems earlier this weekend, her -4 was only enough to keep five players behind her in the total.
The competition was a genre rehearsal for ANA Inspiration, this year's first golf major to be decided next week.