First Aid Kit, Shepherd's Bush Empire, London

Nearly 40 years after Abba burst on the scene, Swedish pop continues to amaze and delight and enthrall. How does it happen?

In the case of 22-year-old Johanna and 19-year-old Klara Soderberg, the Stockholm-raised sisters who make up First Aid Kit, the answer seems to be a combination of astonishingly precocious talent and an immersion in the best that American singer-songwriting has had to offer going back to the 1960s.

The hush that descended on the Shepherd's Bush Empire audience for the opening show of FAK’s latest UK tour told its own story. The strength of their melodies, the bitter-sweetness of their take on life, the gorgeousness of their vocal harmonies, and the power of their stage presence added up to something as enchanting as it was arresting.

The two women were joined by drummer Niclas Lindstrom and the brilliant pedal-steel guitarist BJ Cole – the four of them occupying fixed positions at corners of an imaginary square, with Klara, on acoustic guitar, front stage right, and Johanna, on keyboards, front stage left.

The rigidity of this arrangement was at odds with the wonderful fluency of their songs, none of them lovelier than “Blue”, second on tonight’s set and one of the highlights of their most recent album, The Lion’s Roar.

A seemingly everyday tale of tragedy and loss (someone dies in a car crash, and their lover finds it impossible to love again), “Blue” has about it a mystery that’s at the heart of the best of FAK. Tonight it’s signalled not least by the art-nouveau FAK logo back-projected in vast lettering – itself embellished by alternating graphics of falling snow, of wolves, of deep dark forests.

The FAK aesthetic is as timeless as a Swedish folk-tale, and with their diaphanous dresses and hair cascading down their backs, Johanna and Klara – both of them unfeasibly tall - resembled characters out of one. Johanna overcame the constraints of her keyboard duties with much frenzied mane-tossing, but it was her younger sister who was really in control of proceedings.

She offered up “Hard Believer” for “Mr” Richard Dawkins (“Well I see you’ve got your Bible your delusion imagery/ Well I don’t need your eternity or your meaning to feel free”), and in the most dramatic moment of the evening, announced that she and Johanna were “abandoning modern technology”, at which point the two women stepped away from their microphones and gave us, completely unamplified, an exquisite rendition of their 2009 song “Ghost Town”. The directness of this approach was admirable, and the way Klara slowed the song almost to a standstill represented artistry of the highest order.

“Emmylou” – the duo’s glorious tribute to a quartet of greats in Emmylou Harris, Johnny Cash, June Carter Cash, and Gram Parsons – went down a storm. And they honoured their compatriot Fever Ray with a superb cover of her “When I Grow Up”. They held back a special salute for the encore when they performed their favourite Simon and Garfunkel song, “America” - Klara recalling the “nerve-wracking” experience of playing it in front of Paul Simon himself earlier this year. Though it has to be said that they were slightly less at ease with this than they were with their own material.

If this all makes First Aid Kit sound as if they are merely stuck in the past, nothing could be further from the truth. Wise heads on young shoulders, their reinvention of old sounds was as fresh as a Stockholm morning, and from start to finish this was a concert that just tingled.

Twitter: @SimonOHagan