Elaine Thompson-Herah ran the second-fastest women's 100m time ever - in 10.61 - to retain her Olympic title with a record time for the Games at Tokyo 2020.
The Rio 2016 champion became the quickest woman alive by holding off team-mate Shelly-Ann Fraser-Pryce to take gold, as Jamaica took all three medals with Shericka Jackson claiming bronze.
Britain's Daryll Neita, in her first-ever individual Olympic final, was eighth in 11.12, in a dramatic day on the track. Dina Asher-Smith had earlier missed out on the final and then pulled out of the 200m, revealing that she had been struggling with a hamstring injury.
It was a superb run from Thompson-Herah, who has struggled with injury since winning the 100m and 200m titles five years ago in Brazil. Only American great Florence Griffith-Joyner, in 1988, has run quicker than her. Fraser-Pryce had been favourite to take gold, but even her time of 10.74, which itself is inside the top 10 fastest ever, was not enough to take top spot on the podium.
"I came to this championships wanting to be in the final and I did it so that's a great achievement," Neita told Eurosport.
"The race did not go how I wanted it to go and that's not the position or plan that I wanted to run, but there's always positives to take, so that's what I'm doing."
Gold in the first-ever Olympic mixed athletics relay went to Poland, who won the 4x400m with an impressive kick on the home straight. The Dominican Republic dipped for the line to grab silver ahead of the USA.
Great Britain, who like most teams were without their best 400m runners, finished sixth.