I can see Brazil choking when they face a true true test ie against Germany, Argentina or Spain.
Brazil has a very good track record against Germany in World Cups. It´s usually Germany that chokes when facing Brazil. Of course track record doesn´t mean anything, but still...
As for Spain... Brazil 3 - 0 Spain in the Confeds Cup.
And Argentina has a very bad defense.
They won last match against Brazil (it was in 2012), but then, Brazil was still underperforming with Mano Menezes as a coach plus it had to use VERY inexperienced defenders. Final result was Argentina 4 - 3 Brazil.
Considering that Messi was in better form and scored 3 of the goals, and that the brazilian defense was much worse and inexperienced in that match (Rafael Silva and Bruno Uvini, both Thiago Silva and David Luiz were injured), we can expect Messi in not such a good form would have much more difficulty playing against the much improved Brazilian defense with Thiago Silva and David Luiz (plus Brazil playing much better under Felipão).
All the while, Argentina will have more difficulties scoring against Brazil, but Argentina´s defense has not improved since that match in which Brazil scored 3 goals.