I believe that what helped KRU to become a great team was the fact that they trained against all the high-level Brazilian teams, while the Brazilians did not train among themselves, to hide the tactics.
You always learn something, of course training with Brazil helped, but so did for the Brazilians to train with them, that doesn't take away any credit for what they have achieved
The point I'm making is that they trained with ALL Brazilian teams, without the need to hide tactics (because of the local camps), and that's what made KRU, in my opinion, stronger than the Brazilian teams