Virginia Thrasher of the United States won the first gold medal of the Rio 2016 Olympic Games on Saturday, holding her nerve against two Chinese Olympic champions to clinch the women's 10m air rifle event.
The 19-year-old American edged out China's Du Li, gold in Athens in 2004, with an Olympic-record score of 208.
Defending Olympic champion Yi Siling, also of China, took the bronze medal.
Thrasher was awarded the first gold of the Games by International Olympic Committee (IOC) President Thomas Bach.
Competing in her first Olympics, Thrasher established an early lead after battling with the Russian shooter Daria Vdovina, who stumbled midway through the competition and finished fifth.
Hours earlier, the Olympics were declared open at Rio's fabled Maracana stadium late on Friday with Brazilian marathon runner Vanderlei Cordeiro lighting the cauldron following an exuberant display of Brazil's cultural heritage, capped by breathtaking pyrotechnics – and a burst of high-octane samba.
But the glitter and glamour of Rio's stunning Olympics opening ceremony gave way on Saturday to bitter competition for the first medals.
All eyes will be on US swimming star Phelps, the most decorated Olympian in history, when he returns to the pool in the first week.
Track and field will see Jamaica's Bolt aim to defend his 100m, 200m and 4x100m crowns by clinching all three for the third straight Games.
Gymnastics could unearth a new heroine in America's teenage star Simone Biles, while rugby and golf return to the Olympic programme after gaps of 92 years and 112 years respectively.