Cape Town — World 800m champion Caster Semenya has said that if she loses her legal battle with the IAAF on new rules regulating testosterone levels in female athletes, she will not participate in the World Championships in Qatar this year.

Semenya, whose legal battle has been going on for years, was offered some respite when a Swiss Federal Tribunal set aside the IAAF ruling, saying she could participate in the 800m until a final decision was taken in her case.

The two-time Olympic champion extended her four-year unbeaten streak in the 800m on Sunday after cruising to victory at the Prefontaine Classic Diamond League meeting at Stanford University in northern California.

"This is like a legal battle, like war," said the South African. "You don't give up. If you beat me today, I beat you tomorrow. At the end of the day it's about me, and doing what makes me happy. I'm a world champion, I'm an Olympic champion, I've achieved everything I've ever wanted. I'm doing this for those that cannot fight for themselves", she told AFP.

Semenya has been unbeaten in the 800m event since 2015.