Brazil failed to fire against Venezuela in their Copa America opener on Sunday, drawing 0-0 at the Estadio Unico in La Plata, outside Buenos Aires.
The Brazilians had the bulk of possession, but missed a host of chances that saw Pato hit the woodwork early on and Robinho and Neymar spurned good opportunities.
The five-times world champions continued to pressurise and Robinho almost broke the deadlock after beating goalkeeper Renny Vicente Vega, but Oswaldo Vizcarrondo slid in to block the ball on the line with his shoulder.
With Ganso unimpressive in central midfield, Elano and Lucas Silva came on for the tiring Pato and Ramires with 15 minutes remaining, but the resolute Venezuelan defence - and Roberto Rosales and Vizcarrondo in particular - held firm.
Venezuela are the only South American country never to make it to the World Cup finals, but coach Cesar Farias was full of praise for his players after the game.
"It's historic in terms of the Copa America. Brazil played well but we deserve praise for holding them,'' he said. "When we had the chance play a bit we did and when we had to defend like gladiators we did that too."
In the other Group B match, Paraguay and Ecuador also played out a 0-0 draw in Santa Fe.
World Cup quarter-finalists Paraguay looked dangerous throughout the match, particularly during the opening half-hour when striker Roque Santa Cruz and Lucas Barrios created a number of opportunities.
Perhaps the best chance of the first-half fell to Nestor Ortigoza when Marcelo Estigarribia's cross was not dealt with by the Ecuadorian defence. However, the San Lorenzo man was thwarted by goalkeeper Marcelo Elizaga.
For Ecuador, Cristian Benitez's mazy run and strike midway through the stanza lifted the side, and they carried that attacking verve into the second-half, creating chances through Edison Mendez and Felipe Caicedo.
But neither side could ultimately make the breakthrough, as Santa Cruz's goal-bound header just prior to his departure was spectacularly kept out by the hand of Elizaga.
The results leave all sides in Group B locked on one point heading into their second matches on Saturday, when Brazil take on Paraguay and Ecuador face Venezuela.