Brazilian fans turned on the men's soccer team after a 0-0 draw with Iraq on Sunday that left them in serious danger of exiting at the first stage of the Olympics.
Fans at the National Stadium in Brasilia singled out midfielder Renato Augusto for particular ire, booing his every touch as the game moved into the last 30 minutes.
The Beijing Guoan player missed one of the best chances of the game in added time, volleying over after superb work by Gabriel Barbosa as the multi-million dollar squad failed to score a goal for the second successive match.
The capacity crowd chanted "Iraq, Iraq" and also shouted the name of Marta, the captain of the women's side, who oversaw two victories out of two at the Games last week.
The Iraq stalemate means that Brazil now have two points from two games, the same as the Asians. Both trail Denmark, who have four with only the top two advancing to the knockout stages. South Africa are bottom with one point.
Brazil play Denmark on Wednesday.
The hosts almost fell behind in the eighth minute on Sunday when Mohanad Abdulraheem hit the post for Iraq but Brazil had their chances.
Neymar almost scored direct from a corner kick and Renato Augusto also hit the woodwork with a long-range shot.
Brazil, who could only draw with South Africa in their opening match, had more of the ball and pushed forward in droves as the match wore on but they could not find a way past the Iraqi rearguard.
Brazil had 20 shots at goal to Iraq's eight but they lacked composure as the pressure from a massive crowd in Brasilia grew.
Neymar and new Manchester City signing Gabriel Jesus both disappointed, with Neymar getting a yellow card for petulantly kicking the ball at an opponent.
How Indian athletes fared on Day 2 in Rio
When gymnastics undisputed Queen wished Dipa Karmakar...
In practice, I perform way better than this: Dipa Karmakar
Why this Aussie swimmer is hated in China...
More records fall as legendary Phelps wins his 19th Olympic gold