"And just like that, 20 years," Billie Joe Armstrong marveled in the final seconds of American Idiot closing song "Whatsername" during Green Day's Tuesday concert at the Azura Amphitheater in Bonner Springs, Kansas.

You could see the gravity of it hit him in that moment. Twenty years since the blockbuster American Idiot gave the Bay Area punks a new lease on life and made them one of the biggest rock bands in the world for the second time — just as their meteoric major-label debut Dookie had done 10 years earlier.

With a combined 16 million U.S. sales, these twin peaks cemented Green Day's status as one of the last rock bands of monocultural import. They're playing both in full on their current Saviors tour, named after their new album (which the band has called a spiritual successor to Dookie and American Idiot), and on Tuesday they tore through 37 songs over the course of two hours and 15 minutes with age-defying efficiency.

The different phases of the set showcased Green Day's various strengths — Dookie a vehicle their snot-nosed humor and Beatlesque melodies (endless credit, as always, to bassist Mike Dirnt, whose masterful vocal harmonies elevated the songs), while American Idiot demonstrated their muscular grandiosity and prog-punk theatrics. Thousands of Gen X-ers, many with children in tow, pounded their fists and sang along to slacker anthems like "Burnout" and "Longview," but the concert shifted into next gear during the opening power chords of "American Idiot," bolstered by the screams of those who came of age during Hot Topic's halcyon days.

READ MORE: Why Green Day Initially Shelved 'Good Riddance'

"Put the phones away! Just be here in the moment, right now!" Armstrong implored during "Longview," marshaling the crowd with the zeal of a megachurch pastor or seasoned politician. Yet despite his now-routine jab at former President Donald Trump during "American Idiot" ("I'm not a part of a MAGA agenda"), Armstrong sought to uplift rather than antagonize.

"This is not divisiveness — this is unity!" he shouted during American Idiot fan favorite "Letterbomb." "This isn't just a party — it's a celebration!"

There's been some existential handwringing in recent years whether Green Day qualifies as a classic rock band. Those who came up during the actual classic rock era may balk at the notion, but here are the facts: They've been doing this for nearly four decades, and they're one of a select few rock bands (along with Foo Fighters) capable of packing stadiums while still limber enough to take flying leaps off stage risers. Their hits are part of the pop-culture lexicon and continue to inspire hordes of disaffected young people who take solace in screaming guitars and singalong choruses.

Green Day is well into legacy-act territory now, but they steward that legacy responsibly, inviting starry-eyed young fans onstage every night to sing with them. (Along with the planned audience participation during "Know Your Enemy," Tuesday also featured a brilliant, impromptu duet between Armstrong and a 17-year-old girl during the set-closing 'Good Riddance [Time of Your Life].'") And even if Saviors falls short of the dizzying peaks of Dookie and American Idiot, its highlights show impressive range and fervor, from the Weezer-adjacent "Bobby Sox" to the confessional alt-rocker "Dilemma," one of their best songs of the past two decades.

They might not be your dad's classic rock (unless your dad was born in 1981), but Green Day has earned their classic status, and they still rock with abandon. They're long past the need to prove themselves — all that's left to do now is celebrate.

Green Day Live in Kansas City, Aug. 20, 2024

Punk icons are playing Dookie and American Idiot in full on Saviors tour.

Gallery Credit: Bryan Rolli