Belgian Justine Henin-Hardenne defeated defending champion Amelie Mauresmo of France to claim the season-ending WTA Tour Championship for the first time on Sunday.
Henin-Hardenne, 24, who takes the world number one spot from Mauresmo on Monday, won 6-4, 6-3 in her third major showdown with the Frenchwoman this year.
Mauresmo, 27, beat Henin-Hardenne in the Australian Open, when the Belgian retired due to illness, and at Wimbledon.
It was the sixth title of the year for Henin-Hardenne and 29th of the career.
She reached the final of all four Grand Slams this year and claimed a third French Open title.