Goal-scoring machines Lionel Messi and Thomas Mueller return to the World Cup centre-stage on Saturday after France thrashed Switzerland 5-2 to surge into contention in the tournament.
Argentina can book a place in the second round if they beat Iran while Germany will be virtually certain if they win against Ghana.
Mueller, who hit a hat-trick against Portugal on Monday, is back in action against Ghana on Saturday. German coach Joachim Loew highlighted Mueller's importance influence — and not just his goals — ahead of their game in Fortaleza. "He is unpredictable, he can score at any moment," he said.
"He is a boy who is very motivating for the others. He is funny, joyful. He is very positive, he talks to everybody. He is a real team player. He can transmit his good humour and spontaneity. It is very important for us," declared Loew.
Germany may have to shuffle their defence against Ghana, however, as Mats Hummels struggles with a thigh injury.
Ghana are seeking to recover after their shock 2—1 loss to the United States.
The game will feature brothers on opposing sides. Jerome Boateng will be at the heart of Germany's defence, whilst his half-brother, Kevin-Prince Boateng will be hoping for a start with Ghana.
La Albiceleste raring to go
Argentina's Messi came alive late in the match to inspire Argentina's 2-1 win over Bosnia in their first game. He has called on coach Alejandro Sabella to maintain the three-man attack used in the second half of the game, in a rare public challenge.
Messi said he had been "annoyed" by the more restrained tactics in the first half that held him back.
Gonzalo Higuain is expected to start the Iran match so that he, Messi and Sergio Aguero reform the attack partnership that cracked Bosnia's resistance. And Sabella said he did not mind Messi giving him public advice.
Iran's coach Carlos Queiroz calls the game in Belo Horizonte the most "eagerly anticipated" in Iran's football history.
Nigeria, Bosnia look for seek first victory
Nigeria and Bosnia, both desperate for a win to get them back on course behind Argentina in Group F, play in Cuiaba. Nigeria are currently ahead of their rivals with one point from their draw with Iran this week.
Security tightened
Meanwhile, the World Cup hosts are to boost security around Rio de Janeiro's Maracana Stadium to prevent invasions by ticketless fans, officials said.
Rowdy fans gate-crashed each of the two matches at the iconic stadium so far, raising concerns about security at the venue which will host the July 13 final.
"We are going to establish an extra isolation cordon with mobile fences in the Maracana's sensitive zones and mobilize 600 police in those zones," Rio military police commander Jose Luis Castro told a press conference.
