"Ipurua is the litmus test," he said.
"They put a lot of pressure on you.
"You have to be very attentive to defend these crosses and counter very quickly.
"Everyone suffers here, we did today."
Barcelona no longer have a LaLiga Santander fixture next weekend after El Clasico was called off for security reasons.
"I hope and I trust that we play this match before the end of the first round of fixtures, or at least before the end of the season," Valverde said.
"It's fashionable to not agree on anything on political issues.
"I hope that [there is an agreement] in this.
"I don't think it's too difficult."