The last time they were considered inferior to the opposition was when they took on Madrid in an away league game in May 2008. I was there; so were six Barca fans. Not 6,000, or even 600, but a mere six people.
"How can you claim to be the biggest club in the world when you take just six fans to your biggest rivals?" I asked some fans who didn't go.
The list of excuses went on and on: Madrid is 600 kilometres from Barcelona... difficult for a midweek match... they couldn't face giving them money for a ticket... nor watching their team form a guard of honour to welcome the newly crowned Spanish champions...
Madrid destroyed Barca 4-1 and the Catalans' coach Frank Rijkaard looked a beaten man in the press conference. He departed a few weeks later. Barca had already sent a delegation to sound out Jose Mourinho as his replacement, but president Joan Laporta then insisted that rookie coach and uber-Catalan Pep Guardiola was appointed. It was an inspired decision.
Barca have dominated since and Guardiola deserves much of the credit. His Lionel Messi-inspired charges won six consecutive Clasicos ahead of the current series of four games in 18 days. The winning run came to an end 11 days ago in a 1-1 Bernabeu league draw. The result suited Barca, however, and they remained eight points clear in the race for a third successive Liga title.
But Planet Barca was jolted out of its orbit four days later in Valencia when a sublime extra-time Cristiano Ronaldo header gave Madrid a win in the Copa del Rey final. Once again Mourinho had upset Barca, just as he had done with Inter in the Champions League semi-finals a year ago.
Mourinho was stung by the 5-0 mauling at the Camp Nou in November which reaffirmed Barca's hegemony, but has fought back since. Tactically astute, he used Brazilian defender Pepe to combat and harass the imperious playmaker Xavi. Barca still dominated large swathes of possession, but they didn't score and they didn't win an engrossing encounter.
"There are two ways to combat Barca," says Wigan Athletic's Catalan coach Roberto Martinez. "The South America way, pressing really high to upset their possession game; then there's the European way, dropping deep and hitting on the counter. You need to balance the two."
Round three is tonight and the football world is enraptured. Over 3,400 Barca fans will be in the 80,000 sell-out crowd, with the face value of tickets eye-wateringly high at £70-290 in a country enduring an economic crisis.
Barca remain slight favourites over two legs, even with several defenders missing. The excellent performance of emergency centre-half Javier Mascherano last week in Valencia will allow Guardiola some comfort, though he was uncharacteristically outspoken in Tuesday's press conference at the Bernabeu.
Madrid's Ricardo Carvalho is suspended for the first leg. Ronaldo, Sergio Ramos, Angel di Maria and Raul Albiol are also within a booking of a ban. Given that there have been 21 yellow cards in the three Clasico games so far this season and that Madrid have had players sent off in each of the last three meetings with Barcelona, there could be serious implications for both clubs in the second legs if key players are banned.
There are countless questions ahead of the game. Will Messi play on the wing to allow the out-of-form David Villa a more central role? Villa scored for the first time in 11 games at the weekend in a laboured 2-0 victory over Osasuna, whereas a second-string Madrid team showed their confidence by destroying Valencia 6-3 away.
Will Mourinho tweak his tactics again and start Ronaldo as a false number nine, or start with some of his in-form forwards, given home advantage?
"I'm only dreaming about Wembley," said Andres Iniesta before he was ruled of the clash. Given that he recently became a father for the first time, he's fortunate to be getting enough sleep to dream - but Wembley holds special resonance for Barca fans as it was the venue for their first European Cup win in 1992.
They've won the competition twice since, in 2006 and 2009, but their total of three pales in comparison with Madrid's nine. Los Merengues haven't won the trophy since 2002, when they defeated Barca in the semis. They are hoping that is a good omen - but Barca are vengeful.
- Real Madrid