Iran head coach Carlos Queiroz hailed his players after they opened their campaign in Group F with a gutsy goalless draw against Nigeria.
The unfancied Iranians had the best chance of a grim showdown in Curitiba on Monday when Reza Ghoochannejhad forced a fine save out of Super Eagles goalkeeper Vincent Enyeama in the 33rd minute.
And former Manchester United assistant Queiroz is convinced his side still have a chance in a group which also includes Argentina and Bosnia.
Queiroz said: "I am very happy but it was very difficult, we played against a great team and it was necessary to play a realistic game.
"I think we did well, we fought for every ball and every space, and we played 90 minutes with one thing on our mind - the first opportunity to score.
"It was a game that I need to praise my players, they deserve to be congratulated. We kept the team in the tournament and now we have Argentina. The most important thing is that everything is open for us."