The Barcelona midfielder has admitted to 'stretching his anus' when making a crucial last-ditch intervention to prevent Netherlands winger Arjen Robben scoring a stoppage-time winner in Wednesday's semi-final.
Argentina would go on to book a date with Germany at the Maracana on Sunday following a 4-2 penalty-shootout win, but the price of victory was a 'terribly painful' injury for Mascherano.
"I stretched my anus on that move," he told reporters. "The pain, it was terrible.
"I thought I wouldn't make it. I thought he'd get ahead of me, I thought of so many things, but I did get there.
"I threw myself into it. I could have been sent off. It could have been a penalty. But anyone could have done that, I had the luck to get there."
Mascherano has made over 100 international appearances for Argentina and is their current vice captain.