A band with the buzz of Dead Confederate—the Athens, Georgia wrecking crew and current red-hot critical darling—usually means some agreed-upon stylistic comparisons, and the ones listed on the band’s MySpace and thus most commonly seen by scribblers—Pink Floyd, Nirvana, and Crazy Horse—are all more than fair in this case.

Some of the common denominators among two or all three of those bands include dust-clearing guitar crunch, bluesy, woozy psychedelia, and urgent, tortured singing. To those elements Dead Confederate adds a mournful alt-country patina, with the occasional snatch of soul so that it doesn’t all sound like one, aching slog with a wall of speed-picked guitar behind it. It works, and in the band’s best and most sprawling, protracted songs (often the same thing), it kills.

The Mercury Lounge could barely contain the quintet: Stormy compositions, brooding and ethereal, erupting into guitar squalls and dirty grooves and interrupted only occasionally with thank yous and salutations from frontman Hardy Morris. The tension and desperation hinted at on the band’s September release, Wrecking Ball, felt magnified in almost every selection offered during the one-hour set. “Goner” wasn’t just the restless ache of its album version, but sleepless, pounding torment (“I could be gone / And you would never know,” Morris wails), and “Start Me Laughing” is both goading and gripping—the type of hard-rocking, drawn-out, acid-humored track common to the work of band friend and cheerleader Jerry Joseph. On the disc, “Flesh Colored Canvas” is a near-13-minute voyage that goes on too long for a comfortable listen; live, it’s an epic in the mind-erasing Floyd mode, built for a long and cathartic ride far down in the setlist. “The Rat”—which the band performed a few nights later on Late Night with Conan O’Brien and caused lead guitarist Walker Howle to take a minor spill on that stage—drew the loudest reaction from a crowd that, except for the front few rows, was mostly docile, stationary, and accepting of a promise to be bowled over.

That’s not to be confused with a lack of energy, either, as some show attendees ‘round the blogosphere have suggested. Dead Confederate isn’t so much galvanizing as it is hypnotic—like a post-rock or shoegaze band in that regard, except not so cold. They work you over with the types of crushing rhythms and jangling instrumental fusillades that are probably what endeared them to Gary Gersh, the former Capitol Records president whose past triumphs include Nirvana and Sonic Youth, who signed them to his new label (The Artists Organization).

With that kind of intensity, Dead Confederate didn’t leave much drama untapped for Catfish Haven, who closed the evening with a set stretching just past midnight and let its edgy, ‘70s blues rock jones attempt to carry the night. It was no fault of their own; Catfish Haven were merely stoking where Dead Confederate was overpowering.

Even so, they had plenty to go on. One of Secretly Canadian’s brightest hopes, the band’s name would suggest a hill country blues revue, and that’s not that far off, but Catfish Haven are actually a Chicago-based trio—a return to their original guitar/bass/drums instrumentation from what I’ve been advised was a bulkier lineup, occasionally with a horn section—named after singer/guitarist George Hunter’s Missouri hometown trailer park.

As an overall package, they come off as forceful, if a bit muddled in concert: Fuzzy southern rock at heart with enough garage, indie, and soul curveballs to flavor that stew well beyond generic Skynyrdisms, and one legitimate showstopper (“Please Come Back”) amid a handful of boozy, decent-to-resonant rockers. Their primary asset is Hunter’s singing: A shaggy howl from which you might be able to tease out more delicate, Ray LaMontagne-style roots nuances if you could find your way through a slurry run of punchy emotion and gutteral pleas. That’s all complimentary, mind you; it was impressive how Hunter fit those earthshaking pipes into fist-pumping table-setters and sad-bastard ballads alike while continuing to sound like himself all the while.