Greg Rutherford hailed Lamont Marcell Jacobs' stunning 100m victory as an "out of this world" performance and "one of the biggest shocks of the Olympic Games".
The Italian, a former rival of Rutherford's in the long jump, stormed to a remarkable victory in a new European record time of 9.80 seconds.
Eurosport and discovery+ expert Rutherford celebrated a "special night" at the Olympic Stadium.
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"It was a really open race," said Rutherford. I don't think anybody could call who that winner was going to be. This is probably one of the biggest shocks of the Olympic Games.
"Watching Marcell, a former long jumper, to now become the 100m Olympic champion is such an incredible feat. He had a huge injury that stopped him being a long jumper, he had to change over.
"Long jumpers are generally fast but they are not always that fast! That was out of this world."
Jacobs only ran below ten seconds for the first time in May, and twice lowered his lifetime best during the course of his charge for Olympic glory.
The 26-year-old was behind after the first half of the final after a scintillating start from Fred Kerley but powered past the American.
Rutherford also reserved praise for Kerley, who took a brilliant silver in 9.84 seconds to also beat his own personal best, and his former training partner Andre de Grasse of Canada, who also set a PB with a 9.89 time.
"Fred Kerley has come down from the 400m and is now an Olympic silver medallist in the 100m. It's utterly unbelievable.
"Andre De Grasse is someone I trained with for a while. He's had an up and down time - to come away with another Olympic medal is fantastic."
Gianmarco Tamberi e Marcell Jacobs - Tokyo 2020
Image credit: Getty Images
It was not the only significant action of the night at the Olympic Stadium.
Moments before the 100m finalists assembled themselves on the start-line, Jacobs' compatriot Gianmarco Tamberi secured a shared gold medal with Qatar's Mutaz Essa Barshim.
Venezuela's Yulimar Rojas had earlier shattered the women's triple jump world record, which had been held for more than 25 years.
"We have seen some ridiculously good performances tonight," continued Rutherford.
"[Yulimar] Rojas in the triple jump as well, a world record - mindblowing! She's a remarkable athlete.
"To come away now as the Olympic champion, utterly brilliant for her. It was a massive, massive jump. This turns this into a special night of athletics."
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