Carlos Queiroz has built the Persian Stars into a formidable and physical defensive unit but Stephen Keshi's men need a win if they are to kick on from their 2013 Afcon triumph
Iran and Nigeria will meet for the first time in their history at a World Cup when the Arena da Baixada stadium opens it doors on Monday.
This is Nigeria's fifth World Cup and the fourth for Iran, who qualified for the tournament thanks to their mean defence, which conceded just five goals in 10 Asian qualifying matches.
"Iran's qualification was like a crossing through hell", admitted coach Carlos Queiroz after his team achieved their objective, and for the Portuguese now it is time for the crossing through heaven.
But Nigeria are not a team prone to gifting matches to the opposition and Stephen Keshi wants to show in Brazil why they are the current champions of Africa.
The Super Eagles arrive in South America hoping to improve on their best return from a World Cup; they reached the round of 16 in 1994 and 1998.
Iran do not habitually create many chances but their strength - aside from their mean defence - lies in their aerial threat, and it is this which laid the foundations for their qualification.
Queiroz's men go into Group F as heavy underdogs but if they are able to keep things tight at the back and get the ball into the penalty area from the flanks, they are capable of confounding the doubters.
Nigeria, for their part, are not the team which finished bottom of their World Cup group in South Africa four years ago. Keshi has built a strong, dangerous team who were deservedly crowned kings of their continent in 2013.
Keshi varies his system depending on the opponent, but usually sets his team up in a 4-3-3 formation or a 4-2-3-1 which can become as attacking as a 4-2-4 when the situation allows it.