Caster Semenya of South Africa took the gold medal in the Olympic 800 metres in a personal best time of 1:55.28 seconds.
Burundi's Francine Niyonsaba finished in 1:56.49 seconds to claim the silver, her country's second medal in any sport at the Olympics. Kenya's Margaret Wambui took bronze in 1:56.89.
Semenya has dominated the 800m this season and there had been speculation she could take down Czech Jarmila Kratochvilova's 1983 time of 1:53.28 seconds - the longest standing athletics world record, set in an era when eastern European doping was rife.
After winning the silver medal in London four years ago, the 25-year-old South African has recorded three of the four fastest times in the world this year.
She refused to talk about the gender row that continues to engulf her after winning the Olympic gold. Questions had been raised about Semenya's gender before and during her run to the world title in 2009.
She was subsequently forced to take testosterone-suppressing medication in order to comply with the rules of athletics' world governing body, the IAAF, winning silver in London four years ago.
But last year the Court of Arbitration for Sport suspended the IAAF's rules on 'hyperandrogenism', which causes unnaturally high levels of testosterone, for two years, meaning Semenya could come off the medication.
Earlier this year she set a new personal best of 1min 55.33secs, the fastest time in the world since 2008, and she bettered that in Rio by 0.05s.
The IAAF is set to challenge the CAS decision, meaning the issue is unlikely to go away any time soon.
When all three athletes were asked about the controversy and whether they had been made to take medication, Semenya replied: "Tonight is all about performance, we're not here to talk about the IAAF, some speculations, this press conference is all about the 800m we ran today."
Semenya sees sport as a force for good, saying: "I think sports are meant to unite people. I think that's what we need to keep doing. It's just fantastic.
"I think I make a difference. I mean a lot to my people. That was my main focus - just doing it for my people.
"It's all about loving one another, it's not about discriminating against people, it's not about looking at how people look, how they speak, how they run.
"It's not about being more muscular, it's all about sport. I think about performing. You do not think about what your opponent looks like, you just want to do better. The advice would be for everybody to go out and have fun."
Derval on women's 800m https://t.co/WDNOzV4WO7
— RTÉ Sport (@RTEsport) August 21, 2016
