The 21-year-old, who was the bronze medallist at last year’s World Championships, upgraded in a massive way, as he proved strongest in the closing stages to win the half-lap event in National Record 19.45s.
Americans Kenneth Bednarek (19.62s), Noah Lyles (19.70s), and Eriyon Knighton (19.99s) were second, third, and fourth, respectively, while the Caribbean’s lone representative, Alexander Ogando (20.02s) of the Dominican Republic, was third.
Not only did Tebogo deny Olympic 100m champion Lyles the sprint double, but he also prolonged the American’s wait to crown a male 200m champion since 2004.
Ogando, who has in the past shown his ability over 400m, utilised that endurance to place second in semi-final one. He clocked 20.09s, behind American gold medal favourite Kenneth Bednarek, who stopped the clock in a flat 20.00s.
Bahamian Wanya McCoy (20.61s) and Jamaica’s Bryan Levell (20.93s) were fifth and eighth in that semi-final and failed to progress.
Meanwhile, Botswana’s Letsile Tebogo (19.96s), American 100m champion Noah Lyles (20.08s), and Zimbabwe’s Makanakaishe Charamba (20.31s) advanced from semi-final two, while another American, Erriyon Knighton (20.09s), Liberia’s Joseph Fahnbulleh (20.12s), and Tapiwanashe Makarawu (20.16s), also of Zimbabwe, got the coveted spots from semi-final three.
The men's 200m final is scheduled for Friday August 9.
Noah Lyles, who won 100m gold on Sunday, entered Thursday's final as the clear favourite but could only manage a bronze medal, with US Track and Field subsequently revealing he was suffering from COVID-19.
Fellow American Kenny Bednarek took silver, with Tebogo's time of 19.46 seconds seeing him become Botswana's first Olympic gold medallist in any sport.
They previously won bronze in the men's 4 x 400 relay at the Tokyo Games three years ago, while Nijel Amos took silver in the men's 800m at London 2012.
Tebogo's triumph came just three months after his mother Seratiwa passed away following a brief illness.
After the race, Tebogo held up his spikes to the cameras to display a message detailing his mother's date of birth, before dedicating his victory to her.
"It's basically me carrying her through every stride that I take inside the field," Tebogo told reporters.
"To take her with me, it gives me a lot of motivation. She's watching up there, and she's really, really happy."
Seville, Thompson, and compatriot Ackeem Blake, along with the British Virgin Islands’ Rikkoi Brathwaite and Cuba’s Reynaldo Espinosa, are the Caribbean representatives that remain on course for the final.
Currently the world leader at 9.77s, Thompson was easy in victory in heat one in 10.00s, ahead of Ghana’s Benjamin Azamati (10.08s) and Cuba’s Reynaldo Espinosa (10.11s).
Kenyan stalwart Ferdinand Omanyala topped heat two in 10.08s, ahead of Italy’s Chituru Ali (10.12s) and Joshua Hartmann (10.16s) of Germany. Trinidad and Tobago’s Devin Augustine (10.31s) was fifth in that heat and missed out on the semi-finals.
Great Britain’s Louie Hinchcliffe sprang a surprise to win heat three in 9.98s, upstaging American Noah Lyles (10.04s), who had to work somewhat toward the end. South Africa’s Shaun Maswanganyi (10.06s) secured the third automatic spot in the heat. Naquille Harris (10.38s) of St. Kitts and Nevis missed out.
Seville also ran a relaxed race to finish tops in heat four as he stopped the clock at 9.99s. Japan’s Sani Brown (10.02s) and Thailand’s Puripol Boonson (10.13s) also progressed. Bahamas’ Terrence Jones (10.31s) was fifth in that heat.
Heat five was topped by Nigeria’s Kayinsola Ajayi (10.02s), ahead of Italy’s reigning Olympic champion Lamont Marcell Jacobs (10.05s) and Ghana’s Abdul-Rasheed Saminu (10.06s). Cayman Island’s Davonte Howell (10.24s) was sixth.
South Africa’s Akani Simbine produced a late surge to top heat six in 10.03s, ahead of Blake (10.06s) and Brathwaite (10.13s). Bahamas’ Wanya McCoy (10.24s) and Guyana’s Emanuel Archibald (10.40s) were fifth and eighth, respectively.
American Kenneth Bednarek was joint fastest in qualifying at 9.97s, which he clocked in winning heat seven, ahead of Cameroon’s Emmanuel Eseme (9.98s) and Canada’s Andre de Grasse (10.07s). Jose Gonzalez (10.40s) of the Dominican Republic was eighth.
A stacked eighth and final heat was topped by another American, Fred Kerly, who also stopped the clock in 9.97s. Botswana’s Letsile Tebogo (10.01s) and Great Britain’s Zharnel Hughes (10.03s) also progressed.
Cejhae Greene (10.17s) of Antigua and Barbuda ran well for fourth, but wasn’t fast enough for one of the non-automatic qualifying spots, while Haiti’s Christopher Borzor (10.28s) was fifth.
Thompson, the Jamaican national champion and current world leader in the event, looked set to claim his maiden Olympic gold medal at about the 85m mark before Lyles used his trademark fast finish to just out-dip him in the end.
Both Lyles and Thompson ended with identical times of 9.79 but Lyles won by five thousandths of a second when the times were rounded down. Lyles’ time was 9.784 compared to Thompson’s 9.789.
Fred Kerley, the 2022 World champion, ran 9.81 for bronze.
South Africa’s Akani Simbine narrowly missed out on a medal running 9.82 in fourth while defending champion Lamont Marcell Jacobs of Italy was fifth in 9.85.
Letsile Tebogo (9.86), Kenneth Bednarek (9.88) and Oblique Seville (9.91) rounded out the field.
