Caster Semenya was among a host of winners setting world-leading times and distances on Friday as the 2016 IAAF Diamond League got under way in Doha.
The South African claimed gold in the women's 800 metres in one minute 58.26 seconds.
It was a first Diamond League race victory since 2011 for Semenya, who was forced to undergo gender testing after becoming 800m world champion in 2009 then went on to take silver in the event at the London 2012 Olympics.
In the women's 100m, American Tori Bowie ran a world-leading 10.80s, while her two closest rivals also achieved times under the previous fastest of the year, with second-placed Dafne Schippers of Holland clocking 10.83s and Jamaica's Veronica Campbell-Brown 10.91s in third.
The men's 110m hurdles saw Campbell-Brown's compatriot Omar McLeod improve his own world-leading time from 13.08s to 13.05s.
Another track highlight was Ethiopia's Almaz Ayana running the fastest time of 2016 in the women's 3000m [eight minutes 23.11 seconds].
Great Britain's Eilidh Doyle did the same in the women's 400m hurdles (54.53s), while Kenya's men's 1500m world champion Asbel Kiprop won that event on Friday in a world-leading 3:32.15.
There were also track victories for Ameer Webb in the men's 200m and fellow American LaShawn Merritt in the 400m race.
Meanwhile, the triple jump events saw world-leading marks set by American world and Olympic champion Christian Taylor in the men's competition - 17.23m, beating his own previous mark - and Colombia's Caterine Ibarguen in the women's (15.04m).
