It is one of those nights that will live long in the memory. The band play as if their lives depend on it. The singer commands the stage like a born leader. Their guitarist coaxes barely believable sounds from his instrument. The bassist and drummer are in incendiary form.
And the sold-out crowd loves every moment of it. As the sweat-drenched hordes leave Whelan's, the intimate Dublin venue, a pair of 50-something men can be heard enthusing about what they have just witnessed.
"I haven't seen a gig that good in years," one says to the other. "It was like being in The Magnet all over again," his friend responds, referring to the long-defunct Dublin punk venue that hosted the country's top fledgling bands more than three decades ago. "Only better."
It is remarkable that four Cavan teenagers – whose number includes a 15-year-old frontman – could cause such a stir, but then The Strypes have been the most talked-about Irish band all year. And with good reason.
At the beginning of December they signed a two-album worldwide deal with the venerable US-founded Mercury Records, with an option to extend the arrangement to five albums.
Just two nights before their Whelan's gig, Elton John turned up to a show in a Brighton pub – which is not so surprising when you consider that they are signed to his management company. And the following night, Grace Jones made a beeline for them in London to tell them how much she adored their sound – which has been compared by many to early 1960s Rolling Stones.
They are having to get used to such star power. In November, they were hand-picked by Paul Weller to support him in concert and they got to perform with Weller at Abbey Road, the studio made famous by their beloved Beatles.
They have even made the current issue of Vogue – the magazine has included them in its 'Hot List' for 2013.
With a debut album set to be recorded in January, plus tours to the US and Japan in the offing for the spring, The Strypes are a band going places very quickly indeed.
One place they're not going to, however, is school. Josh McClorey, Peter O'Hanlon and Evan Walsh have already postponed their studies – despite not yet having sat the Leaving Cert – while lead singer Ross Farrelly attends just once a week. Their record company has pledged to provide him with a tutor to help him prepare for the Junior Cert next summer.
"All our focus is on the music for now," says guitarist Josh, speaking to Weekend Review in the company of his three bandmates in the hours before they play that startlingly potent Whelan's show. "We're delighted with the attention we've had so far, but we have to keep our feet on the ground. We're not getting carried away."
The signing of the record deal didn't faze them. Not that they actually signed it – their parents had to deputise as they are all are under 18.
"There had been a lot of interest in us," Josh says, "and we narrowed it down to three major record companies. We went with the one who we felt didn't want to change us."
Spend even a short time in the company of the foursome and it's clear that they have very wise heads on those young shoulders and they haven't let all the praise – from Jeff Beck and Chris Difford of Squeeze and, yes, Elton John and Paul Weller – get to them. "We're not interested in being famous," bassist Peter says. "We just want to play music."
"It's not like The X Factor," Evan, the drummer, adds, his nose curling in disdain. "People who go on that are looking for instant fame – it's nothing whatsoever to do with the music. For us, music is everything. We've been playing instruments for as long as we can remember."
Their tastes are impeccable. They talk excitedly about The Yardbirds and Mick Jagger and mention names from the mid-20th-century delta blues tradition that would elude even avowed music lovers. They speak with a breadth of knowledge that is arresting considering their youth – the oldest, Josh, is just 17. Their skinny, modish suits and mop-top haircuts are redolent of those sported by The Beatles, circa The Cavern Club; even the way Peter wears his bass guitar – high up his chest – recalls Paul McCartney.
Josh, Peter and Evan reckon they first started to learn instruments from around the age of five. Ross shrugs his shoulders. "I just sing. And play the tambourine."
Music post-1970, say, does not seem to hold as much currency for them, although, when pressed, they say they admire contemporary blues-rock revivalists such as Jack White and The Black Keys.
U2 means nothing to The Strypes. "I admire the fact they've been going a long time," Evan says, "but nah, I'm not really into what they do." His words are accompanied by nods of agreement from his friends. It's Chuck Berry, rather than Bono, who floats the boat for these young music lovers.
As the youngest member, Ross also happens to be the quietest. It's remarkable, then, to see his transformation when he stands at the mic stand. With his fringe falling over his sunglasses while commanding that stage, he has the classic frontman look down pat, but it's his vocals that mark him out from the peers – guttural, yet vulnerable. And highly expressive.
He is taking their breakneck success in his stride. "I just love doing this," he says, shyly. There are no pre-gig nerves. "Nah. I never think about that. We're so used to playing live now. And we love it."
The Strypes reckon they have played close to 200 shows in the past 18 months. It's helped make them a super-tight live entity. But even before their very first concert – at Monaghan's Flat Lake arts festival in summer '11 – they had nailed their sound by rehearsing in respective bedrooms.
"We would play music together at every opportunity," Josh says. "We wanted to be confident that we knew what we were doing before we ever played in front of an audience.
"I think that's what bands should do – only play live when you feel you're ready for it. And then, when you're sure about yourselves, try to get as many gigs as you can."
It is sound advice and one that many of their lesser-known contemporaries should take on board before inflicting half-baked music on the paying public.
Yet, the innate musicianship of the quartet should not be discounted. Josh, in particular, is a stunning talent – think Keith Richards-meets-Eric Clapton. There's a virtuosity to the way he plays that's born, not made.
The boys picked up a love of music from their fathers. Evan's dad, Niall, used to be in The Fireflys – a power-pop outfit who briefly put Cavan on the map in the 1980s. He manages The Strypes now and drives them to each show as well as helping out with all the donkey work, such as lugging equipment from one stage to the next.
And, after the Whelan's gig, it is he who drove the band back to Cavan. There are no self-congratulatory after-show parties for this lot.
Already, they are thinking ahead to a New Year's Eve party in the INEC, Killarney, in the company of three of Ireland's best known bands, Something Happens, The Sawdoctors and Aslan.
It says something about their new-found standing that rather than provide the warm-up on the night, it is they who will conclude festivities – although they are not, technically, headlining.
The promoter, in deference to their youth, jokes that he will get in crates of Mi-Wadi for their refreshment.
The Strypes play Dublin's Twisted Pepper venue tonight. A single, 'Blue Collar Jane', is out now.