It wasn’t until the third song of Iron Maiden’s set on Saturday night that it finally dawned on me what I had taken for granted for so long about this band.

It started the moment I zeroed in on Steve Harris as he began the bass intro to “Wrathchild.” I’d heard the song a million times, so I wasn’t super excited to hear it again. I’m pretty sure he’s played it several millions more, yet here he was, running round the stage playing it with the hunger of the twenty-something man he was when he first recorded it.

In 1981.

Now sixty-one, he was playing like he still had something to prove, like he was back at the Cart and Horses or the Ruskin Arms, not just fighting for recognition among all the great bands of the day, but fighting against the music establishment back when punk reigned supreme and metal was proclaimed — as it has been for most of its history — uncool and irrelevant.

One could forgive a band now well into its fourth decade for phoning it in. And to be sure, the show was full of the Maiden trademarks that may be cliches to some but remain red meat to the fans — the giant robot Eddie walking across the stage, the Eddie and Baphomet inflatables,

the “whoh-oh-oh” chants during “Fear of the Dark,” Bruce Dickinson running round the stage like a madman with a British flag during “The Trooper.”

Fault Iron Maiden for any of this if you will, but never, ever fault them for their work ethic. They don’t have to toil this hard to please their audience any more, but on this night — like every night on every tour since they began — they were determined to win over everyone in the sell-out crowd, not with gimmicks but with their own sweat and blood.

Not once during the whole set did they let you forget that this was a real band playing real music, with musical screw ups (once again, “Wasted Years,” the finger points to you) and sound screw ups (Bruce’s intermittent vocal issues throughout the second half of the show, Adrian Smith’s lead levels at various points) that only served to remind us that they were human.

Despite it all,  from the opening notes of “If Eternity Should Fail” to the last chord of “Wasted Years,” Maiden made sure all of us, from the front row of the pit to the last folding chair on the lawn, were drawn in by the intensity, the fervor, the power, the energy of the spectacle. We were watching a supersized club band who, in the words of a song not played on this night, will die with their boots on.

Even the new material proved that Maiden are still a force on the modern music scene. Making up almost half of the whole show, songs like “Speed of Light” and “The Red and The Black” settled in nicely among old favorites like “Powerslave” and “Children of the Damned.” If Book of Souls is any indication, there’s still enough life in these old road dogs to keep them going into a fifth decade and beyond.

I hope — and suspect — that the same may become true of Ghost, who ably warmed up the show to the puzzlement of some of the more grizzled Maiden fans.

Their tight fifty-minute set, anchored by standout cuts “Cerice” and “Mummy Dust” from Meliora, and augmented by Papa’s hilarious “orgasm for Satan” schtick and the “Dueling Banjos” quote in the intro to “Absolution,” showed them confident and more than ready to take on arena-sized responsibility. The only weak point, as it was when I saw them in Rochester at the end of last year, was their last song. “Monstrance Clock” still didn’t provide a definitive ending to their show, especially as most in the audience this time around didn’t know the words to sing along and give it the anthemic quality needed to form an effective conclusion.

But on this perfect Toronto night, there could only be one headliner. Those honors could only go to Iron Maiden — quite simply (with no apologies to James Brown whatsoever) the Hardest Working Band in Show Business.