A first-half goal from Jeison Murillo gave Colombia a 1-0 win over Brazil at the Copa America in a game marred by ugly scenes at the final whistle that saw Neymar and Carlos Bacca shown red cards.
The defeat was Brazil's first in 12 matches and the first game coach Dunga had failed to win since taking over following their disastrous 2014 World Cup.
"It's never a good thing when at the end of a match we're talking about the referee.
"I think if you look at what happened, including at the end, you have to conclude it has something to do with the referee."
The scrappy game threw up few clear chances but Colombia put away the one that mattered to get the win over their illustrious rivals.
This was only their second victory in 10 Copa America encounters against the five-time world champions.
Colombia were the better side throughout with defender Murillo seizing on a loose ball to get the all-important goal nine minutes before half time after a Juan Cuadrado free kick had bobbled around in the box.
Neymar kicked the ball at Pablo Armero in frustration at the final whistle.
Scuffles broke out at the end of the match and Neymar and Bacca were both shown red cards.
The Brazilian had already been given a yellow and will miss Brazil's next match against Venezuela and probably at least one more game.
"Referees need to show Neymar more respect," Willian told television reporters after the game.
"He is always being targeted."
The result leaves Colombia and Brazil tied at the top of Group C along with Venezuela, who play Peru on Thursday.
Remaining Group C fixtures:
Thursday, June 18
Peru v Venezuela
Sunday, June 21
Colombia v Peru
Brazil v Venezuela
Source: Al Jazeera and agencies