Elaine Thompson-Herah claimed an unprecedented sprint double-double at the Tokyo Games on Tuesday after successfully defending her 200m Olympic title with the second fastest time in history. The Jamaican sprinter made it back-to-back Olympic golds in the 100m on Saturday and followed that up with a blistering run in the 200m to become the first woman to win the sprint double in successive Games. Her time of 21.53 seconds was a personal best and sits behind only the world record mark of 21.34secs set by Florence Griffith-Joyner at the 1988 Seoul Games. Namibian teenager Christine Mboma earned the silver medal, with Gabrielle Thomas of the USA taking bronze. Thompson-Herah's Jamaica teammate Shelly-Ann Fraser-Pryce, who was beaten into silver in the 100m, looked strong for a medal but faded in the final few metres to finish fourth. "Honestly I just need to sleep, I have not slept since the 100 metres. My body is in shock mode, but I still had my composure to come out here," Thompson-Herah, 29, said. "I thought my time wouldn't be fast because yesterday we ran two rounds ... so to come out to get a national record and two-time Olympian I am so happy. "It feels good to be in the history book, to set a barrier for the other generation of athletes coming up because we have got a lot of athletes coming from Jamaica, it means a lot to me to set this barrier. "Everyone who supports me and believes in me, a big thank you to them." Runner-up Mboma created her own piece of history as the first woman from Namibia to win an Olympic medal, joining Frankie Fredericks, who won silvers in the 100m and 200m at both the 1992 and 1996 Games, as the only athletes from the southern African country to step on the podium. "It feels great, I am really happy. This is a dream, I just came here for experience. I didn't expect to medal," Mboma, 18, said. "Namibia will be so happy and so proud of me to take the medal back to the land of the brave." On a thrilling day inside the Olympic Stadium, American track and field saw a new star emerge after 19-year-old Athing Mu lived up to the hype by dominating the 800m. Athing set a new national record of 1:55.21 to take the gold ahead of Great Britain's Keely Hodgkinson, another exciting teenager. Few track and field talents come more exciting or dominant than Sweden's pole vaulting champion Armand Duplantis, who blew away the competition to win gold. After comfortably taking the title, the 21-year-old fell just short in his attempts to break his own world record.