The 33-year-old goalkeeper was left devastated after Argentina failed to retain the title they won in Qatar four years ago, with Ferran Torres scoring the decisive goal in New Jersey to deny the Albiceleste back-to-back World Cup triumphs.
Martinez, who played every minute of Argentina's eight matches at the tournament, kept two clean sheets and conceded eight goals as Lionel Scaloni's side reached a second successive World Cup final.
In an emotional post on Instagram, the Aston Villa goalkeeper reflected on the defeat and suggested his international career could be nearing its end.
"I dreamt we'd win it again, I dreamt of bringing it back to Argentina and making history once more," Martinez wrote.
"The truth is, the pain is hard to explain. There are many things to reflect on and how to move forward, and if it's time to step aside.
"I'm so sorry, I truly tried my best to help my country and my team-mates."
Despite the disappointment, Martinez received praise for his display in the final, producing a number of key saves to keep Argentina in contention before Torres struck the extra-time winner.
Martinez has won 67 caps since making his Argentina debut and was instrumental in the country's 2022 World Cup triumph, earning the Golden Glove award as the tournament's best goalkeeper. He also claimed the Yashin Trophy, presented to the world's top goalkeeper at the Ballon d'Or awards, in both 2023 and 2024.
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