Monreal reckons his team must play their very best to give them any chance of success.
"There will be difficult moments, but we have to be together and leave as little space as possible. We must be very generous in our efforts and give our very best.
"It is a match where we will need to give our maximum, and even then we will see whether we will have a chance to scrape a result or not. It seems scary, but it'll be a nice match for the players and fans. It will be difficult, yet exciting."
Monreal refused to consider being on the receiving end of another rout from the champions, after Almeria also suffered a heavy defeat ten days ago.
"People are free to think what they want, and if you give the ball away, Barcelona are able to achieve these kind of results. But every game is different. I do not think it will happen to us as well. If they play very well to attempt to repeat it, we must give them the hardest possible war."