Former Brazil World Cup winner Rivaldo believes that Spain and Argentina will be the two strongest teams at this summer's tournament.
As hosts, Brazil are seen as the favourites to claim the trophy, but Rivaldo, 42, did not pick out his home country when asked about the competition.
"Spain and Argentina are the two strongest teams at the moment," he told Goal.com.
"As we know there are eight world champions who are involved in this tournament, and with all of their experiences, they have all got my respect.
"But Portugal potentially could make an upset."
Rivaldo scored 34 times in 74 games for his country.
