Andres Iniesta blamed errors for Barcelona's Super Cup thrashing by Athletic Bilbao.
Bilbao won last night's first-leg at San Mames 4-0.
"We leave [San Mamés] thinking we can turn it around. It's difficult, but not impossible. We believe we can do it," said Iniesta.
"We made [too] many mistakes and it hurt us. When things don't go the way you want, you have to worry about improving so it does not happen again."