The standard soundbite on Rodrigo Sánchez and Gabriela Quintero has them as a pair of former buskers from Mexico who play heavy metal covers on acoustic guitars. If that makes them sound like a novelty act, it would be hard to argue. But theirs is a show so ear-poppingly dexterous, so ineffably charming and so supremely entertaining that it might even give novelty acts a good name.
The stage set-up - two stools, and very little else, in one of London's biggest theatre-size venues - does not look like much, but the instant they start to play, their hyper-speed virtuosity is mesmerising. Gabriela's hummingbird-handed percussive style looks nigh-on superhuman as she beats intricate rhythms on the body of the guitar simultaneously with her jagged, staccato chords. As unfashionable as it may be to praise such technical flash, it is jaw-dropping and makes two guitars sound like a full band.
The covers sound great - you could even read their version of Metallica's Orion as a play on that era of metal's penchant for flamenco interludes and pseudo-classical asides. But originals form the bulk of the set, and there is no doubting their talent for ornate composition, full of agile textural shifts and catchy lines.
Those busking roots show through in their easy camaraderie with the audience (as do their metal ones, via all the devil-horn hand gestures), and the priority seems to be pleasing the crowd rather than making an artistic statement. But the kick you get out of this awesome show could, for 90 minutes at least, make the faux profundity of so much "serious" rock seem like meagre virtues indeed.
· At Manchester Academy tonight. Box office: 0161-275 2930.