Lionel Messi`s Argentina and France enter the World Cup battle Sunday on a mission to avoid each other in the second round.
Argentina play their first Group F match in Rio de Janeiro against Bosnia, who are making their World Cup finals debut since becoming an independent country in 1992.
In Group E, France play Honduras in Porto Alegre while top seeds Switzerland take on Ecuador in Brasilia.
Two-time World Cup winners Argentina have not reached the semi-finals since 1990. But with an attack force made up of Messi, Gonzalo Higuain, Sergio Aguero and Angel di Maria, they are one of the favourites this time, not far behind their arch-rivals and hosts Brazil.
Coach Alejandro Sabella had a doubt over Napoli striker Higuain, who has been carrying an ankle injury for the past month as Paris Saint-Germain`s Ezequiel Lavezzi has been taking a leading stand-in role in training sessions.
Bosnia know they must expect their opponents to feed the ball to Messi at every occasion. Bosnia`s coach Safet Susic insists, however, that he will not have a man-marker on the Barcelona superstar. The game starts at 2200 GMT.
Group rivals Nigeria and Iran play their first game on Monday. But Sabella will also be keeping a close eye on the Group E games. The winner of Argentina`s group play the second placed Group E team in the last 16 giving France and Switzerland added incentive as they start their campaigns.
France are also eager to put behind them the embarrassing player revolt at the heart of their implosion at the 2010 World Cup when they crashed out in the first round.
The 1998 World Cup winners have lost key playmaker Franck Ribery for the tournament but blasted a weak Jamaica 8-0 in their last warmup game.Honduras will be a tougher proposition in the Porto Alegre match at 1900 GMT however, and France coach Didier Deschamps is preparing his side for a bruising encounter.
The physical Hondurans had Brayan Beckeles sent off in their last friendly against England, whose captain Steven Gerrard described their tackling as "horrific."
Honduras coach Luis Suarez said the tough tactics are nothing to be ashamed of. "We play with a lot of determination and we are intense, but that is allowed and important in football," he said.
"Our attitude is to face the games with character, with hunger, because we are looking as a team to achieve our goals. That is our attitude and I think that is a good thing."
"They are aggressive and know how to defend," said Deschamps, who has brought on a young side with an average age under 26. Only three of the expected French team have more than 50 caps.
Honduras, ranked 33rd in the world by FIFA, are making their third appearance at the World Cup finals. They are still waiting for their first win.
Switzerland are ahead of 16th place France in the FIFA rankings. They are also making a third appearance at the World Cup and have a skillful side coached by one of Europe`s best tacticians, German Ottmar Hitzfeld.
The Swiss also face a tough opener against an Ecuador team who also enjoy a physical encounter, but probably cannot match the exciting Xherdan Shaqiri and other youngsters such as Haris Seferovic, Granit Xhaka and Pajtim Kasami, who have been brought on over the past four years.
Hitzfeld is taking nothing for granted though. "They have some good players, their strength is the counter-attack. Every team has its strengths and weaknesses and Ecuador will have analysed ours."