With three games left to play, that means Dunga's men are guaranteed a place in South Africa.
"Argentina have great players such as Lionel Messi, who could be elected world player of the year. They have a very strong team. But Brazil's technical qualities won out," said the coach.
"I am satisfied to see that we have done our work well, to see the enthusiasm of the Brazilian team and the pleasure with which they played."
Brazil welcome Chile on Wednesday and then finish with a double-header against Bolivia and Venezuela.
Argentina, meanwhile, are hanging on to fourth place after only their second ever home defeat in World Cup qualifying.
They have 22 points, with Ecuador and Colombia both just two points adrift.
Argentina benefited from Colombia's 2-0 victory over Ecuador on Saturday because had Ecuador won, it would have moved them up to fourth.
Diego Maradona's side face a daunting trip to Paraguay on Wednesday before hosting Peru on 10 October and travelling to seventh-placed Uruguay on 13 October.
The man who led Argentina to victory in 1986 admitted his side face a battle to ensure they do not miss out on the finals for the first time since 1970.
"It's going to be complicated for Argentina after this defeat - but we will keep on plugging away," he said. "We have to go to Paraguay to see if we can win the three points. It's going to be tough, complicated and all the more so after today's defeat.
"It's always horrible to lose to Brazil. It always causes you to have a little crisis of confidence but we have to keep working, we mustn't give up."
The home fans showed their displeasure at the manner of the defeat by chanting Dunga's name late in the game.
Maradona cut a disconsolate figure as his team were well beaten
The under-pressure Maradona said he was not worried about his position, adding: "Dunga is doing well and he has very good players. But I am not bitter, I am calm with my players and this will not break me.
"There were moments where we could have got on top - we mustn't jump down their throats. I take full and exclusive responsibility for the loss."
The hosts looked to attack Brazil from the outset in Rosaria, Lionel Messi going wide with a left-footed shot in the 13th minute to rouse the home crowd.
However, it was the visitors who took the lead 11 minutes later when Luisao found himself in acres of space and powerfully headed a Kaka free-kick past goalkeeper Mariano Andujar.
Brazil doubled their lead after Andujar failed to hold on to Maicon's strike from Kaka's pull-back and Sevilla striker Fabiano pounced on the rebound.
Argentina almost reduced the deficit seven minutes later when Rodriguez steered Carlos Tevez's right-wing cross goal-bound but Cesar was equal to it.
Andujar spared the home team further embarrassment with a number of fine saves before they hauled themselves back into contention when Napoli midfielder Datolo marked his first international start by beating Cesar with a rasping effort from about 30 yards.
Argentina's optimism was short-lived, however, as Fabiano met Kaka's slide-rule pass and lifted the the ball over an advancing Andujar.
Several chances came and went but Argentina's first home World Cup qualifying defeat since 1993, when they lost 5-0 to Colombia in Buenos Aires, was never in doubt.
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