Mascherano rounded off an accomplished individual tournament with typically combative performance as Mario Gotze made Argentina pay for missed chances with a superb 113th-minute finish.
Gonzalo Higuain, Lionel Messi and substitute Rodrigo Palacio were all guilty of fluffing their lines in front of goal for the South Americans during a keenly contested encounter at the Maracana on Sunday.
"The pain is immense," Mascherano told reporters after full-time. "We gave what we could and are sorry for us and for the people. This sadness is for life."
Argentina coach Alejandro Sabella is set to step down on the back of his players' final heartache but he paid tribute to their efforts throughout the competition.
The 59-year-old said: "I congratulate the players, who are a pride for the country, on the effort and the championship they did.
"It was a game that either team could have won."
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