Jamaica's Elaine Thompson-Herah completed a second successive Olympic sprint double when she won the 200 metres gold medal in a blistering personal best of 21.53 seconds.
Thompson-Herah controlled the race from the start and was a clear winner, but 18-year-old Christine Mboma of Namibia produced an astonishing final 30 metres to make up four places and take silver in 21.81.
Gabby Thomas of United States took the bronze in 21.87, just edging out 100m silver medallist Shelly-Ann Fraser-Pryce (21.94).
The winning time was the second fastest in history over the distance, behind only Florence Griffith-Joyner's 21.34 at the 1988 Seoul Olympics.
"It feels amazing to win two golds again. I have had a rough week. I haven't slept after the 100m final," she said.
"I really had to pull it out to win the 200m. It's a new PB and a national record. I am so, so happy.
"Honestly I am so tired, my legs just need some rest. I've done so many races in the last few days, but I am very grateful.
"Oh my god, it's amazing that I have ever seen this day. That I could complete another double. I can't believe it."
Great action on the track today as Athing Mu of United States took gold in the 800m, while Jamaica's Elaine Thompson-Herah took 200m gold. #RTESport #Olympics #Tokyo2020 #athletics— RTÉ Sport (@RTEsport) August 3, 2021
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Thompson-Herah defended her 100m title on Saturday ahead of Jamaican team-mates Fraser-Pryce and Shericka Jackson.
Jackson failed to even make the final on Tuesday while the absence of Dina Asher-Smith only aided Thompson-Herah.
The Brit had been expected to challenge for victory but pulled out after failing to reach the 100m final having suffered a serious hamstring injury in June.
Mboma dropped down to the 200m from the 400m, her favoured event, in July after tests by World Athletics found she had high natural testosterone.
It meant the 18-year-old, and team-mate Beatrice Masilingi who came seventh, fell under the same regulations which stopped double Olympic champion Caster Semenya running in the 800 metres.
"This is my first Olympics. I came here for experience but I did better (than I expected). I am really happy with my performance. I am proud of myself," she said.
"In the past, every time I ran against the best athletes I felt nervous. But I don't feel nervous now.
"When I reached the race I lost my nerves and started pushing. I never give up."
Sweden's Duplantis soars to pole vault gold
Meanwhile, world record holder Mondo Duplantis of Sweden won the Olympic men's pole vault gold medal after clearing a height of 6.02 metres on his first effort.
The 21-year-old Duplantis, who finished with a silver medal behind world champion Sam Kendricks of the United States in 2019, remained the only man to fly over six metres this year.
American Chris Nilsen cleared the bar at 5.97 with his first attempt, but could not match Duplantis and picked up the silver medal.
Brazil's Thiago Braz, who won the title at his home Olympics in Rio de Janeiro five years ago, took bronze with his effort of 5.87.
After victory was secure, Duplantis had three failed attempts at 6.19, as he tried to break his own world record of 6.18.