In the story of Arsenal's departure there was an Argentinian at both ends, as well as a hanging judge of a referee. First, Lionel Messi scored the first and third Barcelona goals to confirm his nemesis status, then Javier Mascherano – a player of a less artful disposition – slid in to stop Nicklas Bendtner scoring the late goal that would have put the Gunners through in defiance of all logic and statistics.
The dismissal of Robin van Persie for going through with his shot after the referee had blown for offside was a draconian act which produced much ribaldry among non-Arsenal supporters, who pointed out that the team's only attempt on goal had ended with a sending off. Nineteen shots to nil was Barcelona's boast, along with 724 passes to 119. But it would be wrong not to mention that Barça's wastefulness in both legs contrived to make this a closer, tenser tie than the stats can illustrate.
Messi was messy, at times, in London and here in Catalonia, but his talent will not be denied. Goaded by his own small miscalculations, he ladles out fresh pain. Sometimes he flicks his arms in self‑reproach. Or a mean look slides across his face. His radar was off for 135 minutes, home and away.
When it flicked back on, the ball was juggled into Arsenal's net, and delight took up its usual residence on his face.
Barcelona's current golden age reprises the Johan Cruyff dream teams of the early 1990s. At the heart of it all is a small elastic Argentinian who manages to combine a talent for improvisation with a demonic urge to win.
For almost 45 minutes Arsenal withstood the numbing rhythms of Barcelona's passing. They screened, hustled and blocked without presenting any kind of counter-attacking threat. But then their concentration frayed, possession was surrendered by Cesc Fábregas and Andrés Iniesta swooped, prodding the ball in the third minute of added time to Messi, who flicked it over Manuel Almunia and met it on the other side to apply what felt like the coup de grace.
Until then Barça's attacking play had been relentless but loose, imprecise. Moments before he nullified Arsenal's first-leg lead, Messi had slalomed through Arsène Wenger's defence, only to strike a tame shot at Almunia, who had replaced Wojciech Szczesny. A kaleidoscopic but sometimes sloppy Barcelona performance was raised to something grander by a moment of ingenuity.
Arsenal ran up against the Messi problem here last year when the star of Catalonia watched Bendtner open the scoring and decided an emphatic response was called for. After four strikes by Messi inside 67 minutes, the best Argentinian footballer since Diego Maradona sped down the road to a world player of the year award.
In altered circumstances here (this time Arsenal started with a 2-1 first-leg lead) Messi, Xavi, David Villa and Iniesta already had a provocation to respond to. In boxing they used to say it was a bad idea to hit the young Mike Tyson early in a fight because it just made him angry and hastened the moment of doom. Andrey Arshavin's winning goal in north London three weeks ago had a similarly counter-productive feel. What if it brought Guardiola's Barça past the tiny Camp Nou chapel and on to the pitch like Catalan dragons, looking for a Premier League side to burn?
While Mascherano provided defensive security in front of a back four missing Carles Puyol and Gerard Piqué, the light fell on Messi to show that no team can cope with him when the mood grips him. His unplayability is what sets him apart. In his best form, a chasm opens between the game he is playing and the sport those around him are endeavouring to master.
This was the call to him, on a night of artistic friction. The mission was to blind Arsenal with skill, movement, finesse, audacity. In Theo Walcott's absence Arsenal lacked the spearing penetration of the first leg, when they twice broke free to overturn Barcelona's lead. Van Persie played like an old-school No9 but a revamped home defence seldom back‑pedalled. Instead their midfielders tried to thread passes beyond the oncoming Arsenal throng. Crosses were over-hit, dribbles carried on too long and shots mis-hit until Messi's feet regained their softness, their dexterity, and Barcelona headed for their dressing room in the ascendancy.
The props were in place for another Messi masterclass, and he began the second half in vibrant mood, angling his runs across and maintaining Velcro contact with the ball. But Barcelona were intent on scoring at both ends.
From a Samir Nasri corner, Sergio Busquets headed into his own net before Van Persie was ejected. The Arsenal man had exposed himself to risk with a stupid pull on Daniel Alves in the first half but to remove him for such a minor second offence after a marginal offside call was brutal. With 10 men Arsenal gathered to quell new pressure but Xavi restored parity across the two legs and then Messi stroked in a penalty after Laurent Koscielny had felled Pedro.
Amid the emotional chaos Messi's self-possession was unaffected. He is a gentle soul, always dispensing hurt.