Mr. Wahl, a former Sports Illustrated journalist who later moved to Substack, died while reporting the match between Argentina and the Netherlands, according to NPR.
US reporters sitting near him said he fell back in his seat during extra time, in a part of the stadium reserved for journalists.
They had called for assistance and, while emergency services responded very quickly, they were later told that Mr. Wahl - believed to be 49 - had died.
No further details have been released about his death.
His wife Dr. Celine Gounder thanked those who had "reached out tonight", but added on Twitter: "I'm in complete shock".
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