Day 1 of track and field at the Tokyo Olympics was Friday in Japan, or Thursday night into Friday morning stateside.
The only final of the day was in the men's 10,000m.
Other notable events included: the first rounds of the men's 400m hurdles, women's 100m, women's 800m, men's steeplechase in the earlier session, followed by first rounds of the inaugural mixed 4x400m relay and women's 5000m in the later session, leading up to the men's 10K.
Women's 100m
Prelim Round (8pET)
1st Round (11:15pET)
This round of races perhaps already provided enough evidence to declare Olympic Stadium in Tokyo the home of a "fast track."
Six women went sub-11 in the women's 100m heats, led by Ivorian Marie-Josee Ta Lou's personal-best 10.78 to win heat four — the time trimmed nearly a tenth of a second off her previous top mark from 2018. Here are the others:
10.78, Marie-Josee Ta Lou, CIV (heat four winner)
10.82, Elaine Thompson-Herah, JAM (heat two winner)
10.84, Shelly-Ann Fraser-Pryce, JAM (heat five winner)
10.91, Ajla Del Ponte, SUI
10.95, Mujinga Kambundji, SUI
10.96, Daryll Neita, GBR
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Video: Jamaica's Thompson-Herah crushes 100m prelim, moves to semis
Video: Jamaican Shelly-Ann Fraser-Pryce commands 100m heat in 10.84
SEE MORE: Ta Lou clocks personal-best 10.78 for top 100m prelim time
Men's High Jump
Qualifying (8:15pET)
All three podium finishers from the 2019 World Championships made it through: two-time Olympic medalist Mutaz Barshim of Qatar, and the ROC's Mikhail Akimenko and Ilya Ivanyuk.
American JuVaughn Harrison, 22, attempting the high-long double, also qualified for the final.
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SEE MORE: JuVaughn Harrison, Shelby McEwen qualify in men's high jump
Men's Steeplechase
1st Round (8:30pET)
Ethiopia's Lamecha Girma , the 2019 world silver medalist, clocked the event's fastest-ever heat time at the Olympics in 8:09.83. Behind him in second in heat one was 19-year-old Ryuji Miura of Japan, who broke his own national record in 8:09.92.
Kenya's Abraham Kibiwot and two-time world medalist Soufiane El Bakkali of Morocco were the winners of heats two and three in 8:12.25 and 8:19.00, respectively. U.S. champion Hillary Bor took sixth in heat two and was eliminated. Other national champs also missed the cut: Kenya's Leonard Bett and Ethiopia's Bikila Tadese Takele.
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SEE MORE: Girma, Kibiwot, El Bakkali take men's steeplechase heats
Men's Discus
Qualifying (8:45pET)
Reigning world champion Daniel Stahl of Sweden secured the first men's discus auto-qualifier with a single throw of 66.12m.
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View social media post: https://twitter.com/WorldAthletics/status/1420936208234938369
Women's 800m
1st Round (9:25pET)
The American contingent of 19-year-old Athing Mu, 2019 world silver medalist Raevyn Rogers and American record-holder Ajee Wilson advanced successfully to the semifinals — the former two, making their Games debuts, won their respective heats. Cuba's Rose Mary Almanza, Jamaica's Natoya Goule and France's Renelle Lamote also won.
SEE MORE: U.S. women's 800m trio Mu, Rogers, Wilson advance to semis
Men's 400m Hurdles
1st Round (10:25pET)
Qatar's Abderrahman Samba, world-record holder Karsten Warholm of Norway and American Rai Benjamin – the 2019 world medalists – all won their respective heats to advance.
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Video: Benjamin cruises to 400m hurdles first-round heat victory
SEE MORE: Norway's Karsten Warholm wins 400m hurdles heat with ease
Women's 5000m
1st Round (6aET)
Netherlands' Sifan Hassan, who's attempting the 1500-5K-10K triple, comfortably won heat one in 14:47.89, while Kenyan Hellen Obiri, the two-time reigning world champion and 2016 Olympic silver medalist, took second to world leader Gudaf Tsegay of Ethiopia in heat two, 14:55.77 and 14:55.74, respectively.
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Video: Ethiopia's Tsegay, Kenya's Obiri go 1-2 in women's 5K prelim
Women's Triple Jump
Qualifying (6:05aET)
Two-time reigning world champion Yulimar Rojas of Venezuela secured her spot in the final with a 14.77m mark.
American record-holder Keturah Orji snatched one of the two last qualifying spots with her 14.26m jump.
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Women's Shot Put
Qualifying (6:25aET)
Two-time reigning world champion Gong Lijiao of China heaved 19.46m to advance to the final as the top qualifier, while compatriot Song Jiayuan's 19.23m is next.
American Raven Saunders' 19.22m was the third-best mark out of the qualifying round.
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View social media post: https://twitter.com/WorldAthletics/status/1421054668566765574
SEE MORE: China's Gong, Song, USA's Saunders through to shot put final
Mixed 4x400m Relay
1st Round (7aET)
The United States won its prelim but was disqualified for a late pass made outside the exchange zone. However, less than four hours later, the team was reinstated.
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SEE MORE: U.S. mixed 4x400m relay DQs in prelims on late exchange
Men's 10,000m
Final (7:30aET)
Twenty-one-year-old Selemon Barega, the 2019 world silver medalist, held off world record-holder Joshua Cheptegei of Uganda to return Ethiopia atop the podium for the first time since the back-to-back eras of Haile Gebrselassie and Kenenisa Bekele, who together took home four straight Olympic golds for the East African nation from 1996 to 2012.
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SEE MORE: Barega upsets Cheptegei for 10K gold, 1st Tokyo track medal