In the end, it had to come. The fans came for Messi. For 71 minutes at the Emirates, what they got was Mertesacker as on a taught, thrillingly anxious night Arsenal produced a display of precarious but wholehearted team defence to keep Barcelona’s sinuous attacking talents at bay.

At which point the moment arrived. Enter: Lionel Messi, prelude to what already looks an unanswerable 2-0 away win. Messi had been an intermittent intake of breath all night, popping up here and there to scuttle about with terrifying purpose, then drifting to the right to wait again.

Arsenal had been having one of their better spells but possession was turned over.

In one hard-running movement Barca's blue shirts broke down the left. Neymar, haring into the space behind Hector Bellerin played the most beautifully judged, deliciously causal no-look cut back on the run. Messi took a touch and flicked the ball past Petr Cech – for the first time in his career – with that fine-point left foot.

Crushing blow

It was a crushing blow after more than an hour of deep, disciplined Arsenal defence and occasionally potent breaks. It was also another significant moment for that relentlessly garlanded front three. Messi has a habit of bewildering English teams in the

Champions league

, with a familiar highlights reel of jinks and spins death-blows and tiny little whirling moments of brilliance.

He is only human though. Messi, who always delivers, has delivered slightly less away from home in Europe.Since his hat-trick against Happoel Nicosia in November 2014 the world’s best player came here having scored one in seven away from the Camp Nou in Europe, albeit this being Messi that non-scoring run includes a man of the match performance in the final, and a performance against Manchester City at the Etihad last year that, for 20 minutes or so, was surely as brilliant as anything ever seen on a pitch in England.

Here he made his way slowly into the tie on a freezing night with a sense of quietly simmering intrigue before kick off, not so much the usual ragged pre-match nerves as an air of event-glamour, a spectacle in train. Shiny cards were held up around the stadium, the floodlights flickered, portentous incidental music played, a cauldron of magnificently well-styled event management.

And an entirely fitting stage too, this grand cantilevered steel and glass bowl is the perfect modern Champions League enormodrome. This was an odd, slightly tantalising occasion for Arsenal, a game they would have been happy to simply fast-forward as a 0-0, where no goals was always good news against a team that can win a tie in five minutes of attacking transcendence.

And yet the temptation is always there to seek Barcelona's own tantalising – often illusory – weak points, that whispered vulnerability to a fast start, the ongoing triumphantly successful oddity that is Javier Mascherano, the 5ft 7in centre back, still un-exposed, un-found out, un-monstered.

As it was Barcelona were straight into being Barcelona, a deep blue whirl with or without the ball. Messi picked up the ball in the inside right channel with three minutes gone and skittered at the Arsenal defence for the first time, a reminder of his astonishing speed with the ball at his feet, that cartoonish blur of legs.

Neymar was fouled early on by Hector Bellerin shuttling back. Otherwise he danced about on the fringes for a while. It is of course wrong to focus entirely on that glittering front-line, razor edge of a brilliantly complete footballing machine. Plus, for all the fine practices, the sugary rhetoric, the presence in the starting lineup here of four home-reared players, it is still an extravagantly acquired supremacy.

Arsenal’s entire starting XI at the Emirates cost around £130 million, less than Barcelona’s second and third best attackers combined.

And yet some things are worth whatever you can pay.

With 20 minutes gone there was one thrilling little switch of feet from Neymar, moonwalking in between Bellerin and Aaron Ramsey with a snap of his heels. On the touchline Luis Enrique, dressed for the occasion as a successful San Franciscan graphic designer strode about looking interested in his skinny jeans and fancy trainers, his designer mod anorak.

For all Arsenal’s excellence here the game will always be weighted in favour of that instant, off-the-cuff genius in reserve, talent that can break the most resolutely executed plan.

Arsenal might have taken the lead themselves before Barcelona finally broke and scored, drawing in a instant all the air from the tie. The second goal, eight minutes from the end, killed it, Messi going down under Mathieu Flamini’s tackle and stepping up to spank the penalty home. Guardian Service