The South African won her 30th consecutive race over 800 metres in 1:54:98, crossing the line in Doha emotionless and nearly three seconds clear of her nearest rival.
Having lost her appeal against IAAF rules designed to limit testosterone levels in female runners, it was Semenya’s last opportunity to race naturally at her specialist distance.
The South African was running at the Diamond League meeting two days after the Court of Arbitration for Sport (CAS) rejected her appeal to get the governing body’s (International Association of Athletics Federations) new regulations thrown out.
She must now begin taking medication to lower her testosterone levels if she wishes to compete over that distance based on the new rules, which CAS said on Wednesday were necessary to ensure fair competition.
Under the rules to take effect on May 8, female athletes with high natural levels of testosterone wishing to compete in events from 400 metres to a mile must medically limit that level to under 5 nmol/L, which is double the normal female range of below 2 nmol/L.
Caster Semenya saga takes fresh twist with “I’m finished” tweet
Testosterone is a hormone that increases muscle mass, strength and hemoglobin – which affects endurance.
Semenya won her 30th successive race over the distance in one minute 54.98 seconds.
When asked by journalists after the race whether she would take medication as per the CAS ruling, Semenya replied: “Hell no.”
She added: “Actions speak louder than words,” she said after vying with Dina Asher-Smith’s stunning 200m triumph in 22:26secs for performance of the evening.
“I am never going anywhere, I will always be here. “I understand there’s been a lot of controversy but that does not control anything. It’s up to God. God has decided my career and he will end my career so no human can stop me from running.”
Her response suggested a switch to 5,000m, which is not affected by the controversial IAAF regulation. A week ago she became South African champion over that distance. But she ruled that out, as her sponsors Nike posted a picture of her on social media with the message ‘Never slow down for the world. One day it will catch up with you’.
Semenya also wrote in a statement: “I’m excited winning here in Doha. The first race of the season is tough and you may not be able to predict how your body is going to respond to the push but the weather is great and it was wonderful tonight.
“For me, I believe nothing is hard in life because it is up to you how you take life. As an athlete, I believe in sportsmanship and what sports teaches you is to keep pushing on despite all odds.
“I know life could be difficult at times but I’m a believer and I believe there is always a way to resolve issues. One of my firm belief is that there is always a way out for everything.
“So if a wall is placed in front of me, I jump it. I’m going to keep enjoying my life and live it. I will keep on training and running. To me, impossibility is nothing.
Britain’s Lynsey Sharp finished ninth behind Semenya and revealed she had received hate mail for speaking out about her rival’s dominance.
“I’ve had death threats,” said the Scot. “I’ve had threats against my family and that’s not a position I want to be in, it’s really unfortunate the way it’s played out.”