Five one thousandths of a second,Marcus Erikson or — if measuring by body parts — a clavicle: that was the margin of victory for American sprinter Noah Lyles in the men's 100-meter photo finish sprint Sunday.

Officially, both Lyles and Jamaican sprinter Kishane Thompson finished with the time of 9.79 seconds, though the tight margin prompted the results to be confirmed by photo finish, with Lyles (9.784) just slightly edging out Thompson (9.789) for the gold medal and the title of the fastest man in the world.

Lyles' victory ended a 20-year drought for the U.S. atop the podium at the men's 100-meter dash, as he became the first American to win gold in the event since Justin Gatlin did so at the 2004 Athens Olympics.

Here's everything to know about the rules governing track and field finishes at the 2024 Paris Olympics:

What is the official rule for track and field finishes at the Olympics?

Just after the men's 100-meter race concluded, NBC's Mike Tirico gave a brief explanation of how track and field race winners are determined. In his explanation, Tirico said that Olympic races determine a victor when any part of the leading runner's torso crosses the vertical plane of the finish line.

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USA Track & Field, the governing body that oversees Team USA's international track and field competitions, has similar language published in its 2024 USATF Competition Rules.

On page 67 of the document, under Rule 163 (which concerns running competitions), the first point states: “Competitors shall be placed at the finish line in the order in which any part of their bodies (i.e., the ‘torso,’ as distinguished from the head, neck, arms, hands, legs, or feet) reaches the finish line.”

The sports governing body World Athletics also has similar language in its technical rulebook for track and field competitions.

What did the Noah Lyles 100-meter photo finish look like?

Omega, the official provider of photo finish images at the 2024 Paris Olympics, shared the image of Lyles' victory at the men's 100-meter sprint. The image clearly shows Lyles extending his body forward, with his torso — namely, his shoulder and clavicle — crossing the line before anyone else's.

How did Noah Lyles win gold in the 100-meter sprint?

Lyles, known for being a strong finisher in his races, had to rely on just that, lunging forward to just beat out Kishane Thompson. Lyles had to make ground in the second half of the race after Thompson and other sprinters raced out from the blocks to take early leads.

Men's 100m final results

First-, second- and third-place finishes win the gold, silver and bronze, respectively.

1. Noah Lyles (USA): 9.79 (.784)
2. Kishane Thompson (Jamaica): 9.79 (.789)
3. Fred Kerley (USA): 9.81
4. Akani Simbine (South Africa): 9.82
5. Lamont Marcell Jacobs (Italy): 9.85
6. Letsile Tebogo (Botswana): 9.86
7. Kenneth Bednarek (USA): 9.88
8. Oblique Seville (Jamaica): 9.91