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And the Albiceleste captain admits Saturday's opponents were strong at the back, but says his team are capable of producing far better performances.
"We are first, but we know this level of performance is not as good as we can give," he told reporters.
"Iran closed down well at the back and we really struggled to find space. Still we created a lot of chances.
"Luckily we got the win in the end and got the points, but we have to keep improving."
Argentina goalkeeper Sergio Romero praised the Barcelona star, saying it was a miracle that they won the game.
"Thank God the dwarf [Messi] rubbed the lamp at the end," he said.