Brazil star Neymar said his side have "turned it around" after their 7-1 defeat to Germany in the World Cup semifinals.
The tournament hosts were dismantled by the eventual winners in one of the most stunning matches in World Cup history.
Dunga replaced Luis Felipe Scolari as boss after the tournament, and his side -- who beat France 3-1 in Paris last week -- have now won all seven of his games.
They face South American rivals Chile in a prestige friendly at Arsenal's Emirates stadium on Sunday.
Partiu... LONDRES ️ ✈ @oficialrobinho pic.twitter.com/vQcgDdrMua
- Neymar Jr (@neymarjr) March 27, 2015
The Sun quoted Barcelona star Neymar as saying: "It was tough after what happened at the World Cup, but we turned it around.
"We know people can't drop their heads thinking about what happened. It's past, it's history, it's finished, it happened."
Since then, he said Brazil had "played seven matches, seven great matches -- we were good."
And he added: "We're improving every day. People want us to keep developing. We cannot let our self-esteem drop.
"This scar [the Germany game] will be there and people can be sad, but when they return to the national team they have to have high self-esteem. If not, better stay at home."