Dan Auerbach often looked pained when he sang, as if his words were reverberating through a broken windpipe.
His guitar playing was downright angry at times, equally fluid and fierce, nearly as spiteful as the spurned lovers who populate so many of his band's tunes. The Black Keys frontman was almost a caricature of pent-up emotion being unleashed, quaking and shaking like a suddenly awakened fault line.
He played from his knees, danced with himself, pistoned his nether regions up and down as if his legs were corked with bedsprings, undulating like his limbs were made of taffy.
The tall dude to his right on stage, drummer Patrick Carney, was just as prone to telegraphing his emotions, his face an open book with 60-point type.
At a sold-out Chelsea Ballroom on Sunday night, these two turned their Midwestern take on Delta blues into a contact sport.
They played electric blues with the emphasis on "electric."
When he was fresh out of high school, Auerbach travelled to Mississippi to seek out tutelage from backwoods blues badass T-Model Ford, and to this day you can hear the lessons learned from his time spent in dodgy juke joints: Auerbach's fretwork is just plain mean in places and about as subtle as a drunk attempting to kick down your front door at 2 a.m.
Live, his guitar tone was fuzzy and over-driven, with the heft and power of prime '70s riff rock.
It added serious torque to the Keys' repertoire, where the arrangements were often skeletal and fat-free.
And this was one of the reasons their tunes were so forceful.
To use a boxing analogy, when a fighter puts on too much muscle, it restricts motion and can actually lessen his power.
By keeping their songs lean and sinewy, the Keys hit harder.
And they delivered plenty of body blows at the Chelsea.
Over the years, the Keys' sound has evolved from the primitive stomp of early tunes like "I'll Be Your Man," which Auerbach and Carney tore into like a couple of strays fighting over a steak, to something a bit more textured.
The band's latest disc, "Brothers," from which they played liberally on Sunday, swaggers and struts with bursts of falsetto funk ("Everlasting Light"), white-knuckle R&B ("Tighten Up") and hair-flingin' rock 'n' roll bluster ("She's Long Gone").
Auerbach gave voice to it all in an equally dreamy and possessed moan that often escalated to a shout, delivered with gospel-like fervor, like a preacher at the pulpit confronting some serious sinners. (He was in Vegas, after all.)
His heart's a punching bag, and his words were by turns braggadocious and broken.
He sang of murderers and cheats, desperate times and true love.
It was some pulpy, often gut-wrenching stuff.
"I must admit, I can't explain any of these thoughts racing through my brain," Auerbach howled during the aptly titled "Howlin' For You," and it was just as well.
Some things are meant to be felt rather than intellectualized, a notion almost as perfectly primal as the Keys themselves on this night.
Contact reporter Jason Bracelin at jbracelin@ reviewjournal.com or 702-383-0476.