After four months on the road in support of this year's Attack and Release, it's completely reasonable that the Black Keys might feel the need to chill out a bit. As such, the duo downed water last night at McCarren Park Pool and seemed to be pacing themselves carefully. They played with their usual precision, but we would liked to have seen a little more wildness. The first few songs were subdued, with drummer Dan Auerbach warbling through the opener, “Girl Is on My Mind” (also the first song at their Terminal 5 show in May). “Thickfreakness” chugged along like a train with a broken — or maybe just wacky — axle.

But things started to pick up for “10 AM Automatic,” which had almost a hip-hop beat and an apocalyptic ending, and “Same Old Thing,” during which our friend noted, “It’s getting heavier.” By “Stack Shot Billy,” in which Auerbach mysteriously changed keys, then changed back again — or did we imagine that? — the spell was cast. It helped that there were about 0.9 joints per capita. “What the fuck is that, a helicopter?” someone commented mid-song, apropos of nothing. Things were strange indeed, and wonderful: During “Everywhere I Go,” played as a holy, flaming march, we thought, What’s that sound? A steam shovel, a herd of elk? Meanwhile, Auerbach’s hair, close-pressed to his head at the show’s start, was unfurling.

But things were, in the end, mellow. “Breaks,” a great tune from their no-nonsense first album, The Big Come Up, settled into a funk beat before turning into a leisurely slow jam. The last song of their set, “I Got Mine,” was restrained, and we couldn’t help but think of all the songs we long to hear at a Black Keys show and never do. (Would it have been too heavy-handed for them to have played “Brooklyn Bound”?) When they came on for their encore, Auerbach confided that a cop had approached him next to the stage. “He wanted my autograph,” he said. “The world must be ending.” Dan, we miss when you were running from the law. —Kathleen Reeves