Caster Semenya said “no human can stop me from running” after winning the 800m at the Doha Diamond League meet amid speculation over her future.
It comes just two days after the South African, 28, lost a landmark case against athletics’ governing body.
Semenya challenged IAAF rules designed to limit testosterone levels in female runners but the Court of Arbitration for Sport (Cas) rejected her appeal.
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“Actions speak louder than words,” Semenya told BBC Sport.
“When you are a great champion, you always deliver.”
Victory in the opening Diamond League event of the season was her 30th in a row at 800m.
The double Olympic champion showed no emotion as she crossed the finish line in a new world leading time and meet record of one minute 54.98 seconds, having dominated the race from the start.
Burundi’s Francine Niyonsaba finished second with the United States’ Ajee Wilson third.
On Thursday, Semenya posted a cryptic tweet that suggested she could quit athletics, including a quote which referred to knowing when to walk away.
Under the new IAAF rules Semenya – and other athletes with differences of sexual development (DSD) – must either take medication in order to compete in track events from 400m to the mile, or change to another distance.
She can make an appeal against the Cas ruling to the Swiss Tribunal Courts within the next 30 days.