Jamaica's Elaine Thompson-Herah revealed she had not slept ahead of completing the double double at the Olympics.
The 29-year-old defended her 200m title ahead of Namibia's Christine Mboma and the USA's Gabrielle Thomas in Tokyo on Tuesday.
She set a new national record in 21.53 seconds while rival Shelly-Ann Fraser-Pryce faded to finish fourth.
Elaine Thompson-Herah🇯🇲 has won #gold in #Athletics – Women's 200m at #Tokyo2020 #UnitedByEmotion | #StrongerTogether | #Olympics — #Tokyo2020 (@Tokyo2020) August 3, 2021
It follows her 100m victory on Saturday to ensure she retains both of the titles she won in Rio.
"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."
It's a #silver medal for Christine Mboma of #NAM in the women's 200m after a thrilling final! The first ever Olympic medal for a Namibian woman and the first Olympic medal for Namibia since 1996!@WorldAthletics | #StrongerTogether | #Tokyo2020 | #Athletics pic.twitter.com/9SgFyq4BHt — Olympics (@Olympics) August 3, 2021
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."
