Andres Iniesta smiles when he recalls what one headline in Catalan yesterday referred to as "The Day Everything Began" and another "The goal which changed the history of Barca."
At Stamford Bridge in May 2009, Barca were seconds from elimination against Chelsea in the Champions League semi-final second leg when the ball came to Iniesta.
He struck his injury-time winner through a crowd of players and then ripped off his Barca shirt and ran towards the touchline and the travelling fans.
Coming off the back of a 6-2 win over Real Madrid at the Bernabeu, it was the best week of Pep Guardiola's reign so far and even the normally ultra cool coach ran to join the celebration.
The 1-1 draw meant Barcelona won on away goals and into a final against Manchester United.
"It was just a magical moment - the best I had in my career up to that point," Iniesta said. "I remember the moment the ball went in and we all ran towards the touchline to celebrate. I got so many messages and calls after the game from people I had made happy. It was a big moment for me.
"One minute we were going out and in a second we were through to the final. It is now part of the history of the club."
The playmaker clinched the biggest prize of all a year later when he scored the winning goal in the World Cup final.
"I have seen the replay so many times and it will be a long time before I can watch it without getting that shiver down my spine that you get when you lived through something so incredible."
The Barca fans are calling for what became known as "The spirit of Stamford Bridge" tonight.
Barca have since defeated United twice in the Champions League final and have won 13 of the 16 competitions they have entered under Guardiola, but the coach's fate might have been very different had Iniesta not scored to kick start his magnificent run.
Barca are hoping to become the first team since AC Milan over two decades ago to retain European football's greatest club trophy. Yet despite 86 per cent of Barca fans voting in a newspaper poll that they expecting to win, Xavi is sounding a note of caution.
"The games against Chelsea will be very, very tough," Xavi said. He knows all about the incendiary nature of the matches between the two sides having been punched by Chelsea's Jody Morris in a 3-1 defeat at the age of 20. The teams have met several times since and each encounter has been enveloped by controversy and conjecture.
"Chelsea are physical and quick, with excellent players who have confidence in their new coach," Xavi said. "I've played against [Roberto] Di Matteo [the Chelsea manager] and respect him. He has players like my Spanish teammate Juan Mata - a great footballer. And Fernando Torres, who is scoring again. I know how dangerous he can be. Chelsea have some very strong physical players like Raul Meireles, [Michael] Essien and Obi Mikkel. It's never easy against Chelsea, but we're confident, especially as the return leg is at Camp Nou."
The 2009 match in London also contained a fair amount of spice. Guardiola described the Londoners' efforts in the goalless first leg as "anti-football". Guus Hiddink, the Chelsea manager at the time, preferred to call the bruising stalemate a "man's match".
Xavi, the mild-mannered midfielder, said: "Some of their play was scandalous. So much for talk about fair play. We were the same Barca as normal, dominating. It's just we lacked one little goal."
Chelsea know Barca respect them and they also feel vengeful.
"We are one of the teams which have created the most problems for them," Di Matteo said.
He knows the club are still smarting at what they see at the injustice of a succession of penalty appeals turned down before Iniesta's goal.
"We weren't happy how we were treated," said Di Matteo, who wasn't employed by Chelsea at the time but empathises with the players. Several of his current squad were in that losing side. "We have an opportunity to achieve something unique."
Given Barca's formidable home record, Chelsea's best chance is tonight at Stamford Bridge, the scene of that Iniesta goal.
"This is another game and another situation and we have to make sure we get through this time," Iniesta said. "But there is no doubt that whatever happens, the memory of the goal is one I will never lose."