There's a storm brewing in Liverpool that seems set to tear the roof off this arena. Inside, at the start of their UK tour, Oasis are attempting to prove their fire has not been snuffed out.

The opening chords of "Rock 'n' Roll Star", written when Oasis only wished they were, is the first reminder of what they once meant. "Cigarettes & Alcohol" then sums it up, with the off-hand eloquence Noel Gallagher didn't know he'd lose. "Wait for a lifetime/ to spend your life on the breadline," brother Liam sneers in disgust, his hedonism instead taken as a badge of working-class honour, defying absent long-term prospects.

Add a shamelessly pilfered T. Rex riff, and Liam stretching and chewing syllables like a Burnage Sinatra, and the days when they owned a generation return. But that was so many dull years, and bored records, ago.

Whatever you say about Oasis, of course, that's what Noel has already said first. His greatest song, "Don't Look Back in Anger", warned not to "put your life in the hands of a rock 'n' roll band/ they'll throw it all away" even before they had. He happily confesses he lost his nerve when he should have split his band at Knebworth, the quarter-million-crowd peak from which they could only fall.

The relative strength of their new album, Dig Out Your Soul, is the weariness Noel lets into his lyrics. It feels like an early 1970s record, made after the 1960s gold rush they plundered in their own Britpop heyday.

But that is not why this Liverpool arena, and all the others after it on this tour, sold out in an hour. Their fans are still here because, in their prime, the band made you as thrillingly glad to be alive as they were. That buys you faith, and a decade to coast.

On "I'm Outta Time", Liam rubs his head absently before assuming his statuesque position, as if self-consciously and dutifully the very Last Rock Star. But with a barely digested new album to sell, at times the fans are equally still.

The psychedelic textures and apocalyptic lyrics of "Waiting for the Rapture" sound promising, but leave little trace. The early Nineties B-side "The Masterplan" draws more applause. Back then, every single came loaded with talent and meaning.

Noel is a strange figure to the side, looking on passively at his creation, as if it is out of his control. He steps forward for Oasis's last high-grade single to date, "The Importance of Being Idle". Dedicated, with the sharp wit he keeps from his songs, to Lee Mavers of Liverpool's own one-album wonders the La's, it is playful and almost baroque, a glimpse of a different Oasis. "Wonderwall", by contrast, only needs its opening chords to trigger the communal singing.

Oasis have become a premature oldies act; sad, you might say. But their dauntless youth means they'll always be forgiven.