Barca won 4-1, though had Fermin Lopez sent off in the second-half.
Pedri said: "It was very important. We had a slump in La Liga. We wanted to continue our run and the top teams had equalised. We had to take the three points.
"We started off very well, with a lot of intensity with the ball, but they scored and they got on top. In the second half we came out focused, we scored and it gave us a big advantage.
"I'll say that, with one less player, we knew how to hold the back line, stay in a medium block and when we could get out, we got out. You can also have the ball with one less player."
On Fermin, Pedri added: "Today I told the referee that the other day they gave me a worse one and it wasn't a red card. I don't understand it... But they are the ones who see it. If they have blown the red card, they should always blow it."