Wayde van Niekerk's rivalry with Kirani James and LaShawn Merritt has brought about a new golden age in 400 metres running.
Darya Klishina will compete at the Rio Olympics after her ban from the Games was struck down by sport's highest court on the eve of her event.
Triple jumper Caterine Ibarguen won Colombia's first Olympic gold medal in athletics, building on several years of dominance.
Watch Usain Bolt's reaction to Wayde van Niekerk's WR 43.03 in the 400m final at the 2016 Rio Olympics.
Wayde van Niekerk warned that the "sky was the limit" after smashing Michael Johnson's 17-year-old 400m record when he roared to Olympic gold.
"I still think you need to let it sink it , it is still so fresh I don't think I was in that race tonight. That is how unreal it feels".
Five facts about Wayde van Niekerk, who broke the men's 400m world record at the Olympic Games with a time of 43.03sec in Rio.
"I've got the world record now, and I've got Liverpool! My brother is an Arsenal fan, too, so it was just a great night!"
Wayde van Niekerk, golden boy of South Africa and the world! Van Niekerk obliterated Michael Johnson’s 400m world record.
Wayde van Niekerk prepared for the greatest night of his life by watching Liverpool, in the room he shares with fellow sprint star Akani Simbine.
Wayde van Niekerk won the men's 400 metres gold in a world record time of 43.03 seconds at the Rio Olympic Games.
Luvo Manyonga already knows what he is doing with his silver medal bonus - and its going to blow his mom away!
A first Rio 2016 gold medal for South Africa could be just a few hours away, as Wayde van Niekerk readies for the 400m final.
Luvo Manyonga's family couldn't make it to Rio to watch him win a silver medal, but they haven't stopped celebrating. (VIDEO)