Caster Semenya put all the "nonsense" about controversial new IAAF rules on women's testosterone behind her by storming to victory in a personal best in the 1500m at the opening Diamond League meet of the season on Friday.
"I don't talk about nonsense," the double Olympic 800m gold medallist angrily rebutted when asked about why she never commented on the regulations to counteract hyperandrogenism, the medical condition which causes women to produce high levels of male sex hormones.
IAAF president Sebastian Coe had earlier hit a defiant note amid criticism of the new rules, insisting they were "appropriate for the sport".
The issue is controversial because it pits principles of fair competition against the rights of women born with the condition.
Athletes such as Semenya will only be able to compete when the rules come into effect on November 1 if they take medication to reduce their levels of male sex hormones.
Semenya showed her 800-1500m double at the Commonwealth Games had set up for a fiery start to the season.
She sat in sixth of a loaded 15-strong field through the first lap at the Qatar Sports Club in Doha in temperatures of 30 degrees Celsius (86F).
Pacemakers Emily Tuei and Noelie Yarigo were three seconds off target, taking the field through 800m in 2:11.00.
But Tuei then bolted to the bell, with Semenya in fifth as Kenyan Nelly Jepkosgei took the lead.
With 200m to go Semenya moved effortlessly up on Jepkosgei's shoulder and went past with apparent ease to win in a personal best and national record of 3min 59.92sec.
"The most important thing was to break the magic four minutes, and obviously we did that," said Semenya.
"It was a good race, the most important thing was the finish."