Brazil were a minute away from losing their Copa America group stage meeting with Paraguay before managing a draw to settle early nerves.
But striker Pato says Mano Menezes' side must pull their socks up and make no mistake on Sunday at La Plata with the pair having been drawn to meet again in the quarter-finals.
Menezes spent part of Friday getting his reserve squad to mimic as near as possible Paraguay's style of play in training.
However, after the Brazilians finally "woke up" as their media put it in beating Ecuador to win Group B, they must start favourites with strikers Neymar and Alexandre Pato in their ranks.
Both netted twice against Ecuador - although Menezes will be aware that the Paraguayans are unlikely to allow them as much space coming forward.
Robinho and Ganso will be tasked with keeping the supply lines open to Neymar and Pato with Ramires and Lucas Leiva keeping things ticking over in the midfield engine room.
Pato says that Brazil must be ready from the first whistle - unlike last week, when Fred's last-gasp effort saved a 2-2 draw.
"It will be a tough game and different from the last one in that this time there is no margin for error."
"But we're confident we can win it," said the AC Milan forward.
Given the form of Neymar and Pato, the firepower issue is set to tip the balance away from the Paraguayans, particularly if the latters' Roque Santa Cruz, who netted in the group match, is doubtful through injury after going off in the 3-3 thriller with Venezuela.
"We are hopeful," said coach Gerardo Martino on Friday. "We will give it another day and wait on the results of tests."
Blackburn's Santa Cruz, who after scoring in last week's encounter against the auriverde is his country's joint all-time top marksman with 25 goals, had to go off shortly before half-time against Venezuela after straining a leg muscle and was replaced by Nelson Haedo.
But Martino, who is due to step down after the tournament, is confident that his side has a good chance of reaching the last four as they look to secure a first Copa win since 1979.
"We traditionally do well against the stronger teams," he noted, adding that he believes Ganso, not Neymar, is the dangerman to keep a close watch on.
"It is very important that we don't give him any space," Martino warned.
While Paraguay fret over Santa Cruz, Brazil's injury worry is defender Thiago Silva, who has a similar problem and had a session with the physio rather than take part in the main training session on Friday.
If the AC Milan star does not make it his place will go to Luizao or the less experienced David Luiz.
Brazil right-back Maicon has warned his teammates they have to keep on improving, having only shown flashes of their true talents in the final group game when the chips were down after two earlier draws.
"We know that we cannot just turn up and expect to win games because we are Brazil. We will only get the results we want if we are at our very best," he said.