Joan Laporta has told Barcelona fans to "keep believing" as they head into El Clasico on Sunday looking to hit back from a midweek Champions League disappointment.

A 3-3 draw with Inter on Wednesday was a blow to Barca's hopes of reaching the round of 16, but a win against Real Madrid in one of the most anticipated fixtures in world football would be a perfect response.

The fierce rivals head into the match level on points, with the Catalan giants top of LaLiga by virtue of their superior goal difference.

Barca president Laporta urged supporters to maintain their faith in Xavi and his players, telling BarcaTV: "Keep believing. We have a very competitive team, with very good players who are going to bring you a lot of joy.

"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."

Laporta spoke of his frustration at not securing a win over Inter that would have put their chances of progressing in their own hands.

"It was a big game for us and I am sad and angry that we didn't win despite scoring three goals," Laporta said.

"It was always going to be a difficult group. We should have got a better result in Munich because we were the better team.

"And the refereeing in Milan was scandalous. We shouldn't play the victims card, but we were very unhappy with the match officials, and I spoke to UEFA about it afterwards.

"Financially, missing out on the latter stages of the Champions League is a big blow."