Bellingham scored and also created Joselu's goal in the 3-0 win.
He later said: "It was an important win, they were doing very well. We made a statement of intent to LaLiga; three goals and a clean sheet against a team that was doing very well.
"I feel good with this team. I have freedom of movement, I'm really enjoying my football and being here. Whenever I put on this shirt I always try to do the best I can."
"To be honest, it wasn't a very good finish. Maybe I could have scored another, but the most important thing is the win."
Of his assist, he added: "I've been watching Modrić every day for three months. I just want to be creative. It was a good goal because it took the pressure off us that they put on us at the start."
It's now seven goals and two assists for the England midfielder.
"It's not bad. It's a good start, but the season is very long and I'd like to continue like this. I'm not always going to score or assist, but I'll try to do my best to have an impact on the game."