In a filmed montage of celebrity adoration before the start of the Rolling Stones show on Saturday night at the Barclays Center in Brooklyn, Iggy Pop had a good line. He was remembering seeing the band play in the late ’60s, and he said, approvingly, that hearing Keith Richards’s guitar sound back then felt like being hit with a dead mackerel.

A few times during the concert you kind of knew what he meant. The sound arrived in most of “Midnight Rambler” and parts of “Sympathy for the Devil”: dull-toned, loud, heavy, resonant, forceful riffing. It didn’t happen during Mr. Richards’s processions around the stage, which took him halfway into the arena floor. (The stage fit inside a pair of giant open lips, from the band’s logo; the rounded runway jutting out of it, encircling part of the audience, represented the tongue.) It happened when he stayed local, when he and Ron Wood, the band’s other guitarist, came in close to Charlie Watts’s drum set.

What is a Stones show? Musically, now that they’re in their 50th year and a long time before now, it doesn’t seem to be so much about the performances you’re actually hearing in real time. It’s an oldies show that can become a flickering re-enactment ritual: momentarily you hear a sound that’s both well-worn and alive, with a huge amount of meaning attached to it — it’s almost always a guitar riff or a drum fill — and then it’s gone, pulled under into a more functional or starchier or sometimes sloppier passage. And visually it’s about Mick Jagger’s stamina. Saturday’s show was the start of the American part of the Stones’ “50 and Counting” tour; as long as he was on stage, during the show’s two and a quarter hours, he never stopped. In running shoes and stretchy black clothes he bounced on his toes with knees slightly bent and swinging independently of each other, like a woman in high heels trying to walk in more than one direction.