The Brazilians produced a shocking first-half display but did just enough after halftime to take three points in their first game of a campaign in which they will attempt to win an unprecedented sixth World Cup.
"It's all about efficiency," said Dunga, a former hard-tackling midfielder who has built the team in his own image and included only four recognised forwards in the 23-man squad.
"Everyone has to be efficient, in attack and defence. Without that you don't get anywhere."
Dunga's team have often managed to win matches in which they have been outplayed thanks to isolated moments of individual brilliance, and depend heavily on counter-attacks and set-pieces to score.
"When you meet a team which attacks you, you create spaces," said Dunga, sounding as if he was about to blame the North Koreans for being spoilsports.
"When they are completely closed, it's more difficult to play on the counter-attack and you have to keep plugging away."
He admitted Brazil struggled in the first half.
"At the start we were passing the ball around from side to side. "I'm satisfied with the win but I want more, I want us to score more goals."
