Barcelona midfielder Ivan Rakitic says the Liga leaders cannot afford any mistakes in Saturday's Clasico with Real Madrid.
Barca visit the Santiago Bernabeu holding a three-point lead over their arch rivals and can extend that advantage to six with victory in the Spanish capital.
But Rakitic knows one mistake could allow Madrid to draw level at the summit of the division, saying: "It is not the same as playing against other teams.
"Simply because there are so many special players who are just waiting for one bad pass or something.
"So you have to be ready in every single moment, every single second."
Rakitic is back in contention to feature versus Madrid after returning to training following his recovery from a calf injury.