Brazil open their campaign against South Africa

Brasilia, one of six Olympic football host cities, before facing Iraq and Denmark in Group A. Their biggest threat is likely to come from eternal rivals Argentina. 

Atletico Madrid's Angel Correa and Giovanni Simeone -- son of Atletico boss Diego Simeone -- formed a lethal partnership in scoring 13 goals to win the 2015 South American under-20 championships to qualify. 

They face Portugal in the match of the opening round at the Rio Olympic stadium on Thursday in a group also containing Honduras and Algeria.

World champions Germany can call on the experience of the Bender twins Lars and Sven of Bayer Leverkusen and Borussia Dortmund as two of their overage players.

A return to Brazil holds particularly fond memories for Dortmund full-back Matthias Ginter, who was part of the German squad that won the World Cup two years ago. 

Ginter has shown his commitment to the cause by flying almost 20,000km in four days as he headed back from China with Dortmund on Friday before jetting off to Brazil.

"I'm still young and you have to take the chances offered to you. The Olympics are special. We're all motivated and want to reach the final in Rio," said the 22-year-old. 

Germany start against 2012 gold medallists Mexico in Salvador before facing Fiji and South Korea in Group C. Group B appears the closest to call as Sweden, Colombia, Nigeria and Japan all start with realistic ambitions of reaching the quarter-finals.