Martinez was one of the star performers as the Argentine's secured a tough 1-0 win over Brazil in the final on Saturday.
The result meant Argentina won their first major trophy in 28 years.
Angel Di Maria got the only goal of the game in the first half, with Martinez having to deny Brazil twice after they had good chances to score in the second half.
"There are no words to explain this moment," he said, per the Express and Star.
"It was a dream I had since I was a child. I went to Arsenal at 16 or 17 years old.
"After many years of effort and courage I knew the dream would come."
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