Sometimes it's the little, one-off gigs that are the best. Tonight, Mogwai play a low-key show at the Cambridge Junction, a warm-up set for their headlining slot at this weekend's final ATP holiday camp festival. The band have recently announced a new album, Rave Tapes, which they'll be supporting with a mammoth European tour next year, so to see them play a comparatively cosy venue with the new material still in road-test mode feels like a treat.

A treat which, it must be said, seemingly every fan of emotive instrumental rock in the Fenland is attending. The venue is packed to capacity, filled with a crowd that are soaking up the new material avidly. And it's not hard to see why. The Rave Tapes cuts nod to the band's singular ability to produce music that powers in monumental arcs, but now it's increasingly leavened by textures that have previously fringed the music, aerated by lapping waves of analogue electronics and tuned percussion. The result is as invincible and sure-footed as ever, but seems to draw even more on the moments of steely-eyed elation that have veined the band’s back catalogue. It’s notable how well the stately heft of new album opener ‘Heard About You Last Night’ fits in so well alongside Mr. Beast’s ‘Friend Of The Night’ and Hardcore Will Never Die, But You Will’s ‘White Noise’, all spiralling upwards - this is music that’s undeniably, proudly triumphant, optimistic almost; there’s a reason heads are nodding with such approval.

What strikes, as always, is the nigh-on solid physicality of the band’s sonics. All the Mogwai staples are there: piledriver slabs of guitar, immovable bass and Martin Bulloch's super-human, nay bionic, devastation of drum skins are all on full show on another new cut, ‘Master Card’. Though the Junction's PA may not quite do full justice to the expansiveness of the band's sound, the harder-edged tracks sound magnificent, bristling with the taut punchiness of Hardcore…’s ‘San Pedro’. And then, when they want to, they can draw on torrential extra reserves, as they do on new track ‘Blues Hour’, which taps the delicately wrought songwriting of some of the Ten Rapid material, with Stuart Braithwaite putting in a turn on vocals, working through to a colossal wave of razing guitar by its end.

Beyond the solidity, there's the euphoria. There's plenty of serious appreciation of this series guitar music, but there's also a man windmilling and furiously air-strumming, basking in fretboard heroics so Braithwaite and John Cummings don't have to. At the climax of ‘I’m Jim Morrison, I’m Dead’, a woman reclines onto her partner in a Christ-like pose, overwhelmed by the sheer force… but she's right; there is something epiphanous about the experience. Who'd have thought that something so vaulting, so miraculous could be taking place inside a metal box sited on a scrap of trackside Cambridge? Mogwai themselves give nothing away: apart from Braithwaite, who wields (he’s definitely a wielder, not a player) his Telecaster like he's carving his exacting guitar lines out of a face of granite, the rest of the band execute the songs with determined calm.

When, after an hour, Braithwaite tells us they have two songs left, we should really be feeling sad. But when the first of those two songs reveals itself to be ‘Like Herod’, a small tranche of hell neatly parcelled into 12 minutes of fury, there’s a collective sense of joy, followed immediately by a bracing for the onslaught. With the terrifying calm of a 19th-century Calvinist minister expounding some hateful doctrine, Dominic Aitchison rolls out the debased, ground-down funk of the bass line, followed by the spidery guitar work, all moving towards that moment three minutes in when the maw cracks open. When it comes, it’s so vicious you’d squint even if it wasn’t for the blaze of white light that burns with every needled scream of guitar, and then the band pummel through, a sustained, efficient frazzling of the neural pathways.

While they may be able to summon reverberations from the underworld at will, they wouldn’t leave without playing an encore. First up is ‘Remurdered’, the first track we’ve heard from the new album, built around a sinewy, cyclical synth riff snagged by an undertow of braying noise, which combine to sound massive live, followed by ‘Hunted By A Freak’, touring member and Mogwai associate Luke Sutherland’s violin gilding an excellent, saw-toothed performance of the track.

They close with ‘Mogwai Fear Satan’ and it couldn’t be a more apt choice for the finish, drawing together as it does all strands of the band we’ve had tonight: surging walls of guitar, seismic chord shifts, roiling drums and bristling fragility. There comes a moment midway through when you realise that no-one does long form songs like Mogwai do, when it becomes clear just how transportative their music is, place and time fallen away so that you’re just hanging on the tremulous notes being delivered with such quiet power on stage... And then, just as you’re beginning to shut down, Mogwai blindside you, pulling out one final bludgeoning, a sonic smiting to make sure you’re not getting too sentimental about things. With that and a cheery wave, they’re done. Bring forth next year, bring forth Rave Tapes, bring forth Mogwai.