US and Australian Open champion Naomi Osaka returned to the world number one spot in the WTA rankings on Monday.
Osaka first hit top spot in January, after winning back-to-back majors in New York and Melbourne, making history as the first Japanese player to achieve it.
After seven weeks on top, Ashleigh Barty of Austrailia slips to second with Karolína Plíšková of Czechia in third.
Ranking Under Japan, Not Haiti or the United States
Osaka's mother is Japanese and her father is Haitian. She was born in Japan but spent most of her life in the US, and holds both Japanese and American citizenship. By Japanese law dual citizenship is not allowed. By her birthday, October 16 when she turns 22, she will have to choose Japan or the United States.
Amendments to Haiti's Constitution in 2010 would make her automatically a holder of Haitian citizenship but this has to be officially claimed and has not, but it is always available.