The Chelsea midfielder scored in the 31st minute to guide the Selecao to a 1-0 victory over Ecuador Tuesday night in New Jersey.
Dunga's reign in charge of the Selecao has now overseen two clean sheets, following a World Cup campaign which ended with them conceding ten in just two games.
The Brazilians still had cause for concern at the back against Sixto Vizuete's men, but they held firm for another narrow win courtesy of the Chelsea midfielder's 31st-minute goal.
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Dunga made just two changes to his the side which beat 10-man Colombia on Friday, with Maicon - banished from the squad due to an "internal problem" - and the injured David Luiz (knee) replaced by Danilo and Marquinhos.
Brazil took the lead after a fine move from a set piece after half an hour, a goal which particularly pleased Dunga after his team spent Monday’s training session working extensively on free kicks and corners.
Standing over the dead ball, Oscar played it short to Neymar whose lofted ball through found Willian for a simple finish.
Ecuador responded well to going behind, with Enner Valencia almost equalizing just four minutes later when his low drive rattled Jefferson’s near post.
Neymar, the match-winner against Colombia on Friday, almost doubled Brazil’s lead but could only hit the underside of the crossbar from close range.
Ecuador continued to press and it had few better chances than a header from Valencia which was cleared off the line by Filipe Luis on the hour mark.
The West Ham forward connected at the back post from a well-weighted cross from the right, but his goal-bound effort was first parried by Jefferson before Filipe Luis acrobatically cleared with the outside of his left boot.
The game was end-to-end for much of the second half, with Dunga swinging five changes throughout the period as he trialled the likes of Fernandinho, Elias, Philippe Coutinho, Ricardo Goulart and Everton Ribeiro.
Brazil had another chance to seal the match when Neymar after he was fouled on the edge of the area in the 80th minute.
However, the attacker's shot from the dead ball was deflected wide by Ecuador's Walter Ayovi - and was incorrectly ruled a goal kick by central referee Edvin Jurisevic.
It did not matter, though, as Brazil made it back-to-back victories since the calamitous World Cup campaign ended with consecutive heavy defeats.