Read this in the comments below:
"He says... "The shell. The shell of my mother, Alex. The shell of my mother. 90 minutes. Use your head."
I think he's annoyed he's overdone himself in the game when he's nursing an injury so he's basically saying "You're as fragile as my mum. Don't over do it. Use your head."
The "pa' mi" part is slang, I think."
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""La concha de tu madre" is an insult commonly used in Latin America. They must have argued about Alexis playing 90 minutes for Chile prior to this match, and this expression might have been used by him when saying that it was insignificant.
When Alexis had to retire, Guardiola used Alexis' words and said "La concha de MI madre" (The ****** of MY mother)
"Concha" (Shell in Spanish) is slang for female genitalia

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