Chelsea new centre-back was presented for the first time to the media at Cobham on Tuesday afternoon, he said:
'I think the level is the same because here at Chelsea there are many players that play for their national team. I'm sure that the players here are the same level as the Brazilian team.
'My objective is to compete with these players and be always ready to be selected by the manager. This is a great challenge and I'm sure I'll be happy to take it.
'Even in Brazil people know about his [José Mourinho's] qualities as a manager,' the 25-year-old also revealed. 'I'm sure he'll be very helpful to me.
'He has always been very good to me. I came to Chelsea about four months ago, we had a long chat and he's a very good person and manager.
'Now I'm finally here but I'm still not physically fit. I hope to be in a couple of weeks' time. You always feel a bit anxious to start in a new team and have your first game but I'm used to the physical play with PSV and I'm sure Chelsea will be the same.'