The Primera new-boys were thumped by the Blaugrana on Saturday night.
Pezzolano said: "I apologize to the fans, to the city. They don't deserve such a big defeat. There was no competition. It was regrettable. There are no excuses. We put the best players out there and we couldn't compete. There are many details. It's a short squad. We're going to suffer.
"At the Bernabéu, it was very tiring; then at home we had a direct rival who was very tiring. Then a long trip. In the heat. Here we suffered. We all have to pay for it. The players gave everything they had, but it could have been better. I have never had a defeat like that in my career. We have to look forward.
"They have players between the lines, they know how to play against a low block. There were tactical errors, we suffered. We had them inside our area. They play very well in a high block. The responsibility is always the coach's. I take responsibility. They are a team that plays very well, they manage the spaces well. They are dedicated. We found their best version and we had our worst day."