Defending champions Brazil failed to qualify for the men's Olympic football tournament as a 1-0 loss to Argentina put their rivals through to Paris 2024.
It is the first time since 2004 that Brazil - who were aiming for a third successive gold - will not feature.
Luciano Gondou headed the 77th-minute winner for Argentina's Under-23s at the South American qualifying tournament for this summer's Olympics in France.
Brazil have won a men's football medal at the past four Olympics.
Argentina, who won gold in 2004 and 2008, finished the final qualifying event with five points.
They are one point ahead of Paraguay, who were playing Venezuela later on Sunday in a match that will decide the other qualifying spot. Brazil finished with three points.