Japan's Kimiko Date Krumm beat Spain's Anabel Medina Garrigues 6-3 6-3 to win the Hansol Korea Open in Seoul.
On the eve of her 39th birthday, Date Krumm is just a shade younger than Billie Jean King when the American won in Birmingham in 1983 at 39 years, seven months and 23 days.
It marks a remarkable comeback for Date Krumm, who returned to the tour in April 2008 12 years after retiring.
Date Krumm, who reached the quarter-finals of the Australian Open back in 1992 and who beat top ! seed Daniela Hantuchova in the quarter-finals in Seoul, said: "For the past year, I didn't really know if I could really compete well on the WTA Tour, but it looks okay now.
"I'll have to be careful not to get any injuries, but I think I'll be able to keep playing for a couple of years."
It was Date Krumm's eighth tour title, although before the Korean Open she had lost all eight of her previous matches on the tour.
