At TD Garden, the Black Keys keep it lean

For the last decade, the Black Keys have walked an impossibly thin line. The duo’s greasy, choogling anthems have earned them both astounding mainstream success and a level of critical respectability rarely achieved by old-school purist types. Dan Auerbach and Patrick Carney’s blues-rock formula may not allow for much variation, but when that formula works, it’s hard to imagine anyone else soundtracking your summer barbecue.

Such is the Black Keys’ status that, for the tour that hit TD Garden Friday night, their special guests are indie-rock legends (and fellow unlikely hitmakers) Modest Mouse. Once a scrappy trio, they now number eight musicians, doubling up on instruments so every beat and bass line hit with maximum force. Isaac Brock remains a fascinatingly strange frontman, and his blunt, yawping vocals and scratchy, eerily oscillating guitar cut through even upbeat radio smashes “Float On” and “Dashboard.” When the band leaned into their singular weirdness, as on the stumbling banjo-blues “This Devil’s Workday” and the blistering, hilariously antisocial “Doin’ the Cockroach,” their presence on an arena stage felt like a minor miracle.

The Black Keys’ new album, “Let’s Rock,” is a return to the no-fat, good-times rock ‘n’ roll of 2011 fan favorite “El Camino,” and the lean economy of their 21-song, 90-minute set reflected this clarity of purpose. Auerbach and Carney, aided by two guitarists and the bassist they once foreswore, barreled from one tune to the next, Auerbach chiding himself “we’ll keep it moving” whenever his between-song banter threatened to hit the 15-second mark. The requisite video screen and a giant electric chair that popped up for the encore were the only concessions to stadium-rock spectacle, and while most guitarists in Auerbach’s tax bracket go wireless, his was plugged right into the amp, as if to signal that he wouldn’t be running around the stage or anything.

Though Carney’s kit sat up front with Auerbach, he drummed with a remarkable lack of showiness, forgoing fills and solos in favor of unrelentingly steady timekeeping. Auerbach played with a similar directness; his solos (like his lyrics) were primarily utilitarian, more connective tissue between verses and choruses than virtuoso showcases. While the average Black Keys rocker doesn’t ask much of Auerbach vocally, he proved himself a tender, unassuming falsetto on “Everlasting Light” and a convincingly broken-up soul singer on modern classic “Tighten Up.”

After a steady diet of mid-tempo riff-rock, Auerbach’s acoustic intro to “Little Black Submarines” got the crowd’s (phone) lighters out, though he soon switched back to electric for the song’s crushing, get-the-Led-out second half. Closing the main set with the deliriously fun “Lonely Boy” guaranteed that the three-song encore would be more comedown than peak, though the lizard-brained “Lo/Hi” was plenty fun in its own right. As Carney waved goodbye to the crowd, he held a Miller can in the other hand — a fitting beverage for a band of simple pleasures.

Jessy Wilson brought star-level swagger to her opening set, leading her band in smoldering classic R&B and brawny, Black Keys-adjacent blues-rock.

THE BLACK KEYS

With Modest Mouse and Jessy Wilson. At TD Garden, Friday