Olympics Games Men's Football: The Best Matches, Key Battles, Players to Watch

The Olympic Games men's football tournament starts on Thursday with the opening round of group-stage clashes. Sixteen teams will fight for the gold medal, and they will all be in action on an intriguing opening day. 

Hosts Brazil begin their campaign against South Africa in Brasilia, while Mexico will be looking to make a positive start as the holders take on European heavyweights Germany.

Group by group, here is all the information for the first matchday in one of the Olympics' most intriguing categories. 

Group A 

Iraq vs. Denmark, 5 p.m. BST/12 p.m. ET, Estadio Mane Garrincha, Brasilia. 

Brazil vs. South Africa 8 p.m. BST/3 p.m. ET, Estadio Mane Garrincha, Brasilia. 

Pick of the round: A lot of pressure is riding on Brazil at their home Games, and they will be desperate to make a good start against South Africa in front of their own fans. 

Player to watch: While Neymar is the captain and figurehead of the Selecao lineup, much attention will also fall on the young stars around the Barcelona ace. Gabriel Barbosa, Santos' teenage hotshot, will play alongside Neymar in attack and his goals will be key to the hosts' campaign. 

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Key battle: Tyroane Sandows vs Renato Augusto

Nobody in the South Africa team knows Brazil better than Sandows. The Gremio star may come up against China-based Augusto in the heart of midfield, and he will need to be alert to keep his side from being overrun by the dangerous Selecao. 

Group B 

Sweden vs. Colombia, 11 p.m. BST/6 p.m. ET, Arena da Amazonia, Manaus. 

Nigeria vs. Japan, 2 a.m. BST (Friday)/9 p.m. ET, Arena da Amazonia, Manaus. 

Pick of the round: Group B is the most open in the entire tournament, with each side boasting an impressive pedigree at youth level. Nigeria took the gold medal at Atlanta 1996 and silver in Beijing eight years ago, and their battle with Japan will be unmissable on the first day. 

Player to watch: Chelsea midfielder Mikel John Obi leads his team in Rio de Janeiro, and he has a score to settle after his refusal to play in 2008 led to a temporary suspension from the Nigeria team. The 29-year-old's talents and experience will be vital in leading a dynamic young Super Eagles side.  

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Key battle: Alexander Milosevic vs. Teofilo Gutierrez

Two overage stars clash in Manaus, as Sweden's promising centre-back takes on prolific Teo. The Sporting striker is quick and keen to exploit errors, meaning Milosevic will have no room for error. 

Group C

Fiji vs. South Korea, 9 p.m. BST/4 p.m. ET, Itaipava Fonte Nova, Salvador. 

Mexico vs. Germany, 12 a.m. BST (Friday)/7 p.m. ET, Itaipava Fonte Nova, Salvador. 

Pick of the round: The Olympic champions take on the world champions in a mouthwatering match. Both teams have been compromised by involvement in other tournaments this summer—the Copa America Centenario and Euro 2016 respectively—but there is plenty of talent in each squad to fight for medals at the end of the competition. 

Player to watch: If Germany wish to add the Olympic crown to the World Cup, Max Meyer may be crucial to their chances. The Schalke 04 playmaker is highly regarded, and he has attracted attention from some of Europe's biggest clubs at the tender age of 20, per ESPN. 

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Key battle:  Roy Krishna vs Kim Dong-jun

Fiji have just one player who plies his trade outside of the Pacific nation. Krishna made history in 2013 by scoring the first Fijian goal in the Club World Cup for Auckland City, and he boasts an impressive 19 goals in 27 international appearances. Opposite him will be South Korea's Kim, a veteran of the under-23 categories and keen to make a statement in order to win a place in the senior side. 

Group D

Honduras vs. Algeria, 7 p.m. BST/2 p.m. ET, Estadio Olimpico Joao Havelange, Rio de Janeiro. 

Portugal vs. Argentina, 10 p.m. BST/5 p.m. ET, Estadio Olimpico Joao Havelange, Rio de Janeiro. 

Pick of the round: Admittedly, the clash between Portugal and Argentina would be the talk of the world if Cristiano Ronaldo and Lionel Messi were involved. But even without the two perennial Ballon d'Or challengers, it will be a fantastic clash, bringing together the Group D favourites in an early test. 

Player to watch: For the last six years Sergio Romero has been the undisputed No. 1 in the Argentina net. But Geronimo Rulli now has a golden chance to prove he can fight for the jersey under new coach Edgardo Bauza. A strong showing in Rio would put the Real Sociedad goalkeeper firmly in the spotlight. 

Key battle: Tiago Ilori vs. Angel Correa

Born in Hampstead, England, but representing Portugal at the Olympics, Liverpool centre-back Ilori faces a tough opening test in Rio. Opposite him will be Atletico Madrid star Angel Correa, the biggest name in an Argentina attack that oozes class.