Barcelona will head into the game looking to bounce back from the disappointing 3-3 draw against Inter Milan in midweek which placed their hopes of reaching the Champions League knockout rounds in jeopardy.
Xavi Hernandez's side are top of the La Liga table though, albeit level on points with their upcoming opponents but with a superior goal difference.
Last season, Barcelona defeated Real Madrid 4-0 at the Santiago Bernabeu, the setting for Sunday's clash, and Laporta is optimistic his side can put behind their recent disappointment to achieve a positive result.
"Keep believing. We have a very competitive team, with very good players who are going to bring you a lot of joy," Laporta said on Barca TV.
"Stick behind Xavi, he needs your warmth and confidence. That's what we will give him and we hope the fans do too.
"I have my full faith in Xavi and his staff, and also with the players. We have a great squad and I'm sure they'll bring us a lot of joy. We have a team to compete against anyone in Europe.
"We'll get through this. We won't ever stop working for what we want. This club has had all kinds of ups and downs over the years, but we have always bounced back. And we can still do that, from every part of the club."
Laporta acknowledged just how important Sunday's fixture could be in the title race, adding: "We're top of the league and there's a big game on the way at the Bernabeu.
"El Clasico is very important, whoever wins get a huge injection of morale and the loser takes a mighty blow. It's the kind of game you want to see. We'll go there with our heads held high. We have a team to do things there.
"I hope the players will defend the Barca shirt with the right spirit, because whenever you get knocked down, you have to pick yourself up again. We want to show how good we are and that we can win the league."
