The Brazilian was linked with Arsenal before choosing to join Wolfsburg once it had become obvious that he had no future at Bayern.
He also backed his former side to continue their success under Pep Guardiola.
"Not only them, also Franck Ribery, David Alaba and many others. We often played against each other in practice matches in training and they were competitive, but this of course will be very different.
"Bayern are the best club in the world, you can definitely say that after last season. Every opponent will try to beat them but they have a lot of quality and can do anything they like if they stick together again."
Wolfsburg travel to Bayern this afternoon.