Noa-Lynn van Leuven, 27, who transitioned genders just three years ago, defeated 20-year-old Katie Sheldon, of Ireland, in the finals and was declared winner of the women-only event at the Robin Park Tennis Centre in Wigan.
The news comes after the transgender competitor also won the Challenge Tour against male and female competitors in Germany earlier in the week, according to the Telegraph.
Van Leuven wiped out the number one female player in the world Beau Greaves, 20, of Great Britain, in the double-header semi-finals and then went on to defeat Fallon Sherrock, 29, of Great Britain, also in the semi-finals.
The transgender competitor then played against Sheldon in the finals and came out victorious with a 5-2 match record, per Planet Sport.
Van Leuven's victory resulted in immediate backlash from professional female athletes. Martina Navratilova, the nine-time Wimbledon champion, argued that all sports, even darts, should only permit biological females to compete in women's categories after Leuven's success spurred her to criticize the transgender policy in the sport.
The International Olympic Committee has provided guidance, which the PDC abides by, as does the Darts Regulation Authority. Two of the IOC's ten guiding principles are "inclusion" and "no presumption of advantage." Sports have been urged to take into account "disproportionate advantage, which needs therefore to be mitigated" on an individual basis, according to the Telegraph.
A group of 26 academics, however, contested this policy last week, claiming that "the inclusion of transgender women in female sports categories cannot be reconciled with fairness."
The Darts policy states that a gender identity cannot be changed for at least four years and that transgender players must have a testosterone level below 10 nmo/L for at least 12 months.
This incident serves as just the latest example of trans-identified biological male athletes dominating women's sports.