The Brazil winger has been a key influence on the LaLiga leaders, with performances that include hitting a hat-trick against Real Valladolid.
Raphinha said: "Since I arrived, I would say that I am going through my best moment. But I feel that I can still improve a lot more and that I can help a lot more with the improvement that I can still have.
"I see that we are doing very well. In the end, when you win the first four games, things become easier. I know that from the outside, people are excited about us. But we also know that the season has just started and we have to continue like this.
"The four games have already passed and now we have to think about what is coming, the next games, the one against Girona, which is the next one. In my opinion, the team is quite focused, and working hard and well.
"The whole squad is focused on the season and we believe that we can do many good things."