It's no longer in Spain's hands.
After losing to the USA, Spain are in danger of losing the top spot in the FIFA Ranking. Spain's chances of fending off the Brazilians rest with the USA. Spain must defeat South Africa (avoiding PSO) and hope USA do the same against the Seleção. Any other combination of results will hand the top spot to the Brazilians.
Basically, if Brazil avoid losing to the USA (no PSO), they will return to first place, a position they lost in September 2007.