Caster Semenya dominated the 800 metres women's race at the season-opening Diamond League meeting in Doha, amid speculation she could retire after losing her case against the IAAF. 

The South African powered to a world-leading and meet-record time of one minute and 54.98 seconds after a superb second lap. 

Semenya put clear daylight between herself and the chasing pack, with Francine Niyonsaba and Ajee Wilson coming second and third respectively.  

The Court of Arbitration for Sport (CAS) on Wednesday dismissed the two-time 800m Olympic champion's appeal against the IAAF's testosterone regulations in a landmark legal case. 

The IAAF's ruling will require Semenya to take medication to reduce testosterone levels in order to compete in track events ranging from 400m to a mile. 

Initially, Semenya stated that she will "rise above and continue to inspire young women and athletes in South Africa and around the world" in response to the CAS decision. 

However, a cryptic tweet on Friday that included the quote, "Knowing when to walk away is wisdom. Being able to is courage. Walking away with your head held high is dignity" prompted speculation Semenya might retire, leading to an outpouring of support from fans urging her not to do so. 

"For me, this is life. In life, it's hard sometimes, sometimes it's good, but there's nothing that can stop me living in this world," the 28-year-old said after the race, as quoted by the Independent. 

"I think it’s all about keeping believing. If kids look up to you, you must keep doing what’s best for them.  

"This is no longer about us, it’s about the future, the next generation. So we keep inspiring them and then life goes on." 

An appeal can be made against the CAS decision to the Swiss Federal Tribunal within 30 days of the ruling. The IAAF's rules are set to come into effect on May 8.