London: Barcelona will seek to seal their status as the finest team of their generation on Saturday when they face Manchester United at Wembley in the most eagerly-anticipated Champions League final in years.
A second triumph in three years - and their third since 2006 - will provide irrefutable proof that Pep Guardiola's team deserve to be bracketed alongside legendary teams like Real Madrid's 1950s vintage, Johan Cruyff's Ajax or the Dutch-influenced AC Milan of the 1990s.
Blocking the route to immortality, however, are United, the newly crowned English champions who are desperate to avenge their bitterly disappointing defeat to the Spanish giants in the Rome final two years ago.
United manager Sir Alex Ferguson has never spoken in detail about what he believes went wrong in 2009, when his team were taken for a dizzying ride on Barcelona's famous midfield "carousel" in a 2-0 defeat.
The obvious temptation for Ferguson as United attempt to avoid a repeat of that chastening experience, is to bolster his midfield with an extra man.
Yet to do so would mean having to sacrifice the burgeoning partnership between Wayne Rooney, back to something close to his best, and Javier Hernandez, the young Mexican striker who has been the find of United's season.
The bolder option would be to keep faith with the midfield formation which served United so well en route to the final: a central pairing of Ryan Giggs and Michael Carrick flanked by Antonio Valencia and Park Ji-Sung, with Rooney dropping deep when Barcelona are in possession.
Ferguson has hinted that he is leaning towards a tactical approach that is more in keeping with United's attacking traditions.
"We have players who can cause any team a lot of bother and hopefully those attacking players will give Barcelona the problems that everyone thinks they are going to give us," Ferguson said.
"It's not just about Barcelona, it's about us too. We have to work out what gives us the best chance of winning the match. It will be down to how we operate the attacking part."
Yet the threats for United are obvious and many.
To prevail at Wembley they will have to come up with a gameplan that neutralises an attack led by Lionel Messi, operating in front of a bejeweled midfield encrusted with the twin talents of Andres Iniesta and Xavi Hernandez.
Messi has been in magical form for Barcelona in Europe, contributing 11 goals and evoking tributes from some admirers that he already deserves to be ranked alongside the likes of Pele and Diego Maradona.
One more goal on Saturday will see Messi equal Ruud van Nistlerooy's record of 12 in a single Champions League campaign.
But displaying the sort of modesty that is part of the diminutive Argentinian's appeal, Messi says he is not interested in personal milestones.
"Goals are only important if they win you games," Messi said. "If I don't score and Barcelona win the Champions League, it's unimportant whether I find the net or not. My interest is in the collective success of the team."
Ferguson is confident however that Messi can be dealt with.
"We have played against Barcelona three times with Messi in the team," Ferguson said. "But there is always a solution to every good player. Hopefully we can find one on Saturday."
United will take encouragement from the fact that other teams have already demonstrated that Barcelona can be vulnerable against opponents who counter-attack at speed.
Arsenal scored a 2-1 victory over the Catalans in the last 16 first leg in February, stunning Guardiola's men with two late goals to claim a narrow advantage.
The asterisk against that memorable night in north London however is that Barcelona would have been out of sight by half-time had it not been for uncharacteristic profligacy by Messi and David Villa in an opening period where Arsenal's defence was sliced open repeatedly.
The message Ferguson has been drumming into his players is that one lapse of concentration on Saturday could be fatal.
It was slack play that led to Barcelona's early opening goal from Samuel Eto'o in Rome two years ago, setting United on the path to defeat.
"We lost the first goal due to that sudden lapse of concentration, that was what cost us really," Ferguson reflected. "After that they withdrew Messi into central midfield and that made it very difficult for us.
"So concentration is going to be important in terms of attacking and defending. That will be the key for us."