Former Liverpool manager Jurgen Klopp has revealed why he used to support Barcelona against Jose Mourinho's Real Madrid, admitting that the aggressive defending of Pepe and his teammates made him favour the Catalan giants.

Klopp, now in charge of the Germany national team, was asked about Sunday's El Clasico at Camp Nou, where Mourinho will once again lead Real Madrid into a confrontation with their fiercest rivals.

Speaking to DAZN during Wednesday's Champions League encounter between Bayern Munich and Arsenal, the 59-year-old explained that his previous preference for Barcelona stemmed from his frustration with the physical approach adopted by certain Madrid defenders.

The German singled out former Portugal international Pepe, whose confrontations with Barcelona's attacking players became a defining feature of the rivalry during Mourinho's first spell in charge between 2010 and 2013.

However, Klopp insisted that his sympathies are no longer determined by those memories, revealing that he now approaches the fixture from a more neutral perspective.

That has not stopped him from identifying Barcelona as the stronger side ahead of Sunday's meeting, with Hansi Flick's men enjoying a perfect start to their La Liga campaign.

Klopp recalls Pepe's aggressive approach during Mourinho's first Real Madrid spell

Klopp has followed El Clasico throughout his career, even while managing Borussia Dortmund and Liverpool, and considers it one of football's most compelling rivalries.

"Of course I'll watch El Clasico between Barcelona and Real Madrid. I've watched this game at every stage of my life," he told DAZN.

But the former Liverpool boss admitted that his enjoyment of the fixture was once accompanied by a clear preference for Barcelona.

"In the past, I was more of a Barcelona fan because I hated it when Pepe and the other defenders were kicking anything that moved back then," Klopp explained.

"That was the only reason I supported Barcelona more."

His comments bring back memories of the particularly heated encounters between Mourinho's Madrid and Pep Guardiola's Barcelona during the early 2010s.

The two managers oversaw contrasting footballing approaches, with Guardiola's possession-based Barcelona frequently coming up against a Madrid team renowned for their intensity, pressing and physical competitiveness.

Pepe was among the most controversial figures in those fixtures, often tasked with disrupting Barcelona's attacking combinations and limiting the influence of Lionel Messi.

The Portuguese defender's aggressive challenges became a recurring talking point, particularly during the series of four Clasicos played across three competitions in the spring of 2011.

One of those encounters saw Pepe sent off during Real Madrid's Champions League semi-final first leg against Barcelona, which the Catalans won 2-0 at the Santiago Bernabeu.

Mourinho's side nevertheless enjoyed notable success against their rivals during that period, including victory in the 2011 Copa del Rey final and the 2011-12 La Liga title.

Klopp's remarks were directed at the behaviour of Madrid's defenders rather than constituting a personal attack on Mourinho.

Yet their timing is notable, with the Portuguese manager now back at the Bernabeu and preparing for another crucial meeting with Barcelona.

Klopp backs Barcelona's form ahead of Sunday's El Clasico

While Klopp's former allegiance was influenced by the physical nature of Real Madrid's defending, his preference ahead of this weekend's encounter is based on the respective performances of the two teams.

"Today, I'm supporting whichever team is better. And as things stand, that team is probably Barcelona," the Germany coach explained.

His assessment reflects Barcelona's extraordinary start to the 2026-27 La Liga season.

Flick's side have won all nine of their opening league matches, scoring 39 goals and establishing a six-point advantage over Real Madrid.

That attacking output has underlined the effectiveness of the German's approach, with Barcelona combining relentless pressing, quick transitions and fluid movement in the final third.

Their unbeaten start to the season across all competitions ended earlier this week, however, when Paris Saint-Germain secured a 4-2 Champions League victory against the Spanish champions.

The defeat exposed some defensive vulnerabilities, particularly when opponents found space behind Barcelona's high defensive line.

Madrid, meanwhile, head into Sunday's contest following a convincing 4-1 Champions League victory over RB Leipzig, although their domestic performances have been considerably less consistent.

Mourinho has faced the challenge of integrating several attacking stars while attempting to establish a settled starting XI.

Kylian Mbappe remains central to Madrid's attacking ambitions, but the Portuguese manager must also contend with Vinicius Junior's suspension and the increasing influence of summer signing Yan Diomande.

Barcelona will nevertheless enter the Clasico as league leaders, knowing that victory would extend their advantage over Madrid to nine points after just 10 rounds.

For Mourinho, the occasion offers an opportunity to narrow the gap and demonstrate that his side can compete with Spain's most in-form team.

For Klopp, meanwhile, Sunday's encounter will provide another chapter in a rivalry he has followed for decades.

Although the combative defending that once pushed him towards Barcelona is no longer the deciding factor in his allegiance, the former Liverpool manager still believes the Catalans have the edge.

The match takes place at Camp Nou on Sunday, October 25, with kick-off scheduled for 8pm UK time.