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 when Reza Ghoochannejhad forced a fine save out of Nigerian 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."
Iran's delight in taking a point was evident in their reaction at the final whistle while Stephen Keshi's Nigeria will see the draw as an opportunity lost.
The Super Eagles were found wanting with their final ball throughout and only the late addition of substitutes Shola Ameobi and Peter Odemwingie breathed life into their front line.
Keshi admitted: "The boys were nervous and unsettled - you don't do that at this stage.
"It happens in football. We really didn't perform as expected but we have to move on.
"I wanted a win but we must take a draw. We must do better to get a win against Bosnia."