Catalans Dragons 33 Wigan Warriors 16
Wigan suffered a case of big stage jitters as they tumbled to defeat in the historic Nou Camp showdown.
Their performance was far more messy than Messi as the Dragons scored four unanswered tries - including two from David Mead - in the second-half.
It was not the El Clasico that neutrals had craved and for Wigan, it was a miserable display - a relapse after a recent upturn in form.
Around 4,000 Warriors fans were in the declared crowd of 31,555 - a record attendance for a regular Super League game - but their side could not deliver on the grandest stage of all.
Still, there was something quite surreal for the supporters as they watched on, from the sun-washed stands, as the players clashed at one of the world's most iconic venues.
There was a carnival atmosphere from the start and given the vast number of Catalans fans in the Barcelona ground, that was only heightened when their side cut loose in a second-half.
Dragons coach Steve McNamara said both sides had a responsibility to put on a spectacle; his side certainly delivered with a vibrant attack in the second-half.
Wigan only trailed 8-6 at half-time and had a golden chance to go ahead early from the restart.
But from then on, they crumbled, and the defensive grit they had rediscovered in recent weeks slipped away far too easily.
It was a much different performance from a week ago and yet Wigan - wearing black armbands in tribute to the late Quentin Pongia - were unchanged for the first time this season.
With ex-Warriors Sam Tomkins and Matty Smith absent, Catalans started forward Greg Bird at halfback until his early loss through injury, while former Wigan players Lewis Tierney and Micky McIlorum faced their former club.
Catalans, decked out in a stylish Barcelona FC-inspired shirt, went ahead through a seventh-minute penalty when Sam Powell was pinged for a tackle infringement.
But errors flooded into their display, gifting Lam's side chances - Joe Greenwood went closest when he attempted to ground Thomas Leuluai's stabbed kick through.
For all their possession, Wigan were far too loose, and the game reached the quarter-mark without a try being scored.
They then suffered the loss of Greenwood to a leg injury - Chris Hankinson replaced him - and seconds later McIlorum's strength and sheer determination powered him over the line for the opening try. Tony Gigot's conversion made it 8-0.
The Warriors had some bite to their defence early on, and it needed great tackles from Oliver Gildart and Zak Hardaker to shut down Dragons attacks before the break.
But with the ball they were poor and, on the one occasion they looked sharp, they scored.
A crisp attack to the right saw Dan Sarginson release Liam Marshall - with suspicions of a forward pass - and the winger blazed away from the scrambling defence to arc over. Hardaker's conversion cut the margin to two points by half-time.
And the full-back's early break put Wigan into the ascendancy from the restart, but Marshall had a second try chalked off by the video referee after going into touch before diving in at the corner.
That mistake came back to bite them, as Catalans blitzed their opponents with three tries during a whirlwind eight-minute spell which opening up a 26-6 lead by the hour-mark.
Sam Kasiano stripped the ball from Sean O'Loughlin and had the physical presence to send Mead over.
Gigot struck the conversion and a subsequent penalty wedged a 10 point gap between the sides with half-an-hour to play.
And Wigan's woes deepened when Samisoni Langi and Kasiano punished a brittle defence. Gigot rubbed salt into the wounds with a drop-goal.
And it only got worse for Lam's side, as Mead pounced on a loose ball to race away and inflict a rare blowout defeat on the Cherry and White.
Gildart swept over for a consolation try and then, on the whistle, Hardaker chased his own kick to grab their third and at least ensure the scoreline had a touch more respectability.
Catalans: Gigot; Yaha, Mead, Wiliame, Tierney; Langley, Bird; Bousquet, McIlorum, Moa, Edwards, Whitley, Casty. Subs: Garcia, Simon, Baitieri, Kasiano.
Wigan: Hardaker; Marshall, Sarginson, Gildart, Burgess; Williams, Leuluai; Flower, Powell, Navarrete, Isa, Greenwood, Clubb. Subs: O'Loughlin, Tautai, Bullock, Hankinson.
Referee: Ben Thaler