Xavi has urged his side to learn from their recent performances against Espanyol and Intercity after a couple of underwhelming showings after the World Cup.
Barca followed up the weekend’s draw with Espanyol with a wild 4-3 win over Intercity, needing extra-time to see off the third-tier side.
Xavi admitted he wasn’t too happy with the way things went and felt his team should have killed the game off earlier.
“We can’t be happy but these things can happen in the Copa,” he said.
“Seven top flight teams have been knocked out. We did not kill the game off when we were in front. We could have made it 0-2, 2-4, but we made things difficult for ourselves. We were not good enough in both boxes.
“It’s the same feeling we had after the Espanyol game. That was a warning and this is another one.”
Barcelona now head to Atletico Madrid for a tricky league clash made even tricker as top scorer Robert Lewandowski will not be available.