Fall in love and dance: Calexico live in London

Their compelling mix of warm, earnest alt-country and lively mariachi influences has a rare accessibility- one doesn't need to be intimately familiar with the band's substantial back-catalogue to appreciate live performances that marry technical proficiency to a vibrant, un-ostentatious aesthetic that's pretty easy fall in love with - and even easier to dance to.

But tonight's concert at London's Barbican (25 April) saw them at their absolute peak, which is quite something for a band that have been around just short of 20 years. More than a few acts of their vintage simply don't look like they give a damn any more, lethargically plowing through the same old songs with the verve of a provincial tax official, but Calexico retain the spark of a group who still genuinely love performing. While they don't often deviate from the template they set themselves back in 1997, over the years they've become more assured, better at balancing their more subtle, acoustic material with the more immediately satisfying trumpet-punctuated numbers. They've brought more prominence to stylishly-sideburned guitar wizard Jairo Zavala, who adds genuine rock star flair to proceedings with his shredding solos and strutting charisma. They've even bulked up their sound with synths, which makes them sound more like the E Street Band every time I see them. The core of the band remains the same, but the little tweaks around the edges definitely prove to be greater than the sum of their parts.

One thing that remains constant about Calexico throughout the years is their synergy with their support acts. Usually, the most an opener can hope for is a shout-out by the headliner - at best. But tonight, Calexico appears as the backing band for charming Guatemalan singer-songwriter Gaby Moreno (incidentally, co-writer of the Parks and Recreation theme), and she in turn pops up regularly during the main set, lending her jazz-tinged vocals to the likes of "Moon Never Rises" and "Miles From The Sea". In the past, they've meted out similar treatment to Sam Beam and Beirut, and it works well- it makes the evening seem like one seamless whole, rather than two entirely disparate, unconnected sets.

But the best is saved to last. Of course there's the obligatory airing of "Guero Canelo", perhaps the most energetic song in their oeuvre, where lead singer Joey Burns, after several failed attempts throughout the evening, finally managed to coax the audience into a full-throated call-and-response routine. There's an unexpected and utterly delightful cover of David Bowie's "Five Years", sung partially in Spanish by Ms. Moreno. But most of all, there's the moment where the band decide to fully utilise the superlative acoustics of the Barbican Hall and perform an entirely unamplified version of "Across The Wire". Sometimes moments like that can fall flat, especially in a venue that voluminous, but tonight it seems like the perfect final touch to an exceptional evening.