New Zealand golfer Lydia Ko has slipped two places to number five in the latest women's world rankings.
Ko has struggled on the LPGA tour in recent months and failed to make the cut at last week's British Open.
Two-time major champion American Lilia Vu is the new number one.
She rose from number six after her victory at the British Open in Surrey.
Vu, a 25-year-old from California, overtook Nelly Korda, who dropped to number two.
This is the first time in rankings history that Americans have been number one and two.
Vu becomes the 17th different player to reach number one as well as the fourth American since the inception of the Rankings in 2006.
"Being the best in the world, that's just crazy to me," Vu said following Sunday's victory in Surrey, England. "Just thinking about the struggle I had this year and just to come out with that has been -- it's just incredible."
Despite her struggles, Vu won the first three tournaments of her career in 2023, which ties her with France's Celine Boutier for the most wins on the season.
She won the Honda LPGA Thailand in February and her first major, The Chevron Championship, in April. Vu has also clinched a spot on the U.S. Solheim Cup Team.
Lydia Ko spent 125 weeks as world number one, the last time she was number one was at the start of the year.
-Reuters