Pa Mamadou Gai was 22 years old at the time of the Sydney Olympics, and was making his second Olympic appearance, having previously represented The Gambia at the 1996 Summer Olympics. On 22 September, he participated in the first round of the men's 100 meters race, and was drawn into heat eight. He finished the race in 11.03 seconds, eighth out of nine competitors in his heat, and was eliminated. The gold medal was eventually won in 9.87 seconds by Maurice Greene of the United States; the silver was won by Ato Boldon of Trinidad and Tobago, and the bronze was earned by Obadele Thompson of Barbados.