Caster Semenya, South Africa's 800-meter world champion, said on Thursday that she was ready to defend her title in South Korea in August after winning her first ever 400m race.

"I think I'm ready for the 800," Semenya said, who won the 400m in 54.03 seconds in a national athletics series.

"It's what I'm training for so I'm just going to train hard so I can retain my title. I think I'm good enough to retain my title," said the 20-year-old.

Semenya was still recovering from a back injury which stopped her competing at the Commonwealth Games in India last October.