Miranda met a corner from Neymar in the 92nd minute and headed past goalkeeper Sergio Romero to hand Brazil a third victory in the "Superclasico de las Americas."
The match at King Abdullah Sports City in Jeddah featured few other chances for either team.
Argentina was without superstar Lionel Messi, and striker Paulo Dybala was ineffective up front in a match where players from both teams complained about the heat.
An emotional Miranda dedicated the goal to his wife on the 16th anniversary of their first meeting.
Brazil's next friendly will be in London against Uruguay in November as the team continues preparations for the Copa America tournament it will host next summer.
Argentina's interim coach Lionel Scaloni said the test was positive regardless of the result.
"A lot of players were in their first Superclasico, they will achieve great things," he said. "Doing what we did today we will fight a war against everyone that plays us."