El Clasico at the Bernabeu on Sunday could be pivotal in deciding one of the most fascinating La Liga title races for years.
There are only 13 games remaining in the season, and despite both sides looking unconvincing and weakened by injuries, Barcelona lead Real Madrid by two points at the top of the table.
Real, particularly, will need to overcome a poor run of form at home if they want to regain the title initiative.
They haven't won in three straight games in all competitions, losing 2-1 to Manchester City in the Champions League in midweek, held 2-2 by relegation-threatened Celta Vigo in the Spanish league and beaten 4-3 by Real Sociedad in the Copa del Rey.
“We know it's a delicate moment, with three games without a victory in our stadium,” Real coach Zinedine Zidane said.
“But these things can happen, we have to stay positive. We will need our fans supporting us from the first minute to the last. I understand why they are upset, but we need them now. And they need us. We need to stick together.”
Real's form against Barcelona at home also is not good, with four straight league losses, and winless in seven consecutive games against Barca in all venues and competitions.
Barca coach Quique Setien tried to downplay Real's poor run, saying: “Madrid is always dangerous, playing at home or not.
"For Madrid this is a vital game, a lot more than it is for us, for sure. It’s a key match. If we win we open a five-point lead.”
Setien will also count on Lionel Messi, who will be playing in his 43rd clasico.
“I would love to see Messi play 43 other clasicos," Setién said. “He is a very important player and hopefully he will have a great match and help us win.”
