SA's Akani Simbine finished fourth for the second consecutive Olympic Games as the American Noah Lyles claimed the gold medal in the men's 100m sprint.

The USA's Noah Lyles won the Olympic gold medal in the men's 100m sprint on Sunday night in a photo finish with a time of 9.79 seconds, a mere five-thousandth of a second quicker than Jamaica's Kishane Thompson.

Lyles became the first American men's Olympic 100m champion in 20 years, since Justin Gatlin in 2004 at the Athens Games.

South Africa's Akani Simbine placed fourth for a second Olympic Games in a row, coming in at 9.82 -- a national record. He was just pipped at the line by the USA's Fred Kerley, claiming his second Olympic 100m medal after his silver in Tokyo.

Lyles was slow out of the blocks and Thompson led from the start, but Lyles' top-end speed took him past several athletes to clinch the victory with his final stride over the finish line.

Because of the tightness of the race, there were no immediate celebrations at the conclusion amid uncertainty over the winner. Eventually, Lyles was announced as the winner at the Stade de France.

On hearing the announcement, the flamboyant American, who claimed a bronze medal in the 200m in Tokyo, ripped the racing bib off his...