Alan Kardec managed to break the Costa Rican defensive wall in the 67th minute as Brazil reached their seventh World Cup final in this age group.
They have won four titles, with the latest registered in UAE in 2003.
Costa Rica defended in numbers since the kick-off to avoid another humiliation at the hands of the Brazilians.
They lost 5-0 in the group stage and coach Ronald Gonzales adopted a 4-5-1 formation to stop the Brazilian attacking waves.
After an eventless first-half, Brazil registered the winner when Kardec hammered the ball into the roof of the net from an acute angle.
Ghana's game is a repeat of the 1993 final when Brazil were crowned champions after a 2-1 triumph.
Meanwhile, Ghana have never won the title despite playing in three final games.