Rapper YG performs at the Fillmore Silver Spring. (Kyle Gustafson/For The Washington Post)

He’d already gotten them to shriek and shout and bounce their butts. So near the end of his set at the Fillmore Silver Spring on Friday night, YG initiated a group confession.

It came during “Sorry Momma,” an apology to his mother for the uncounted misdeeds he raps about in other songs. “I know I did wrong,” YG shouted. “I know I did wrong,” hundreds of fans shouted back. And for a moment, a Friday night in the club was a Sunday morning in the pews.

While the rapper was touching hearts, DJ Mustard was touching bone marrow. YG’s producer, DJ and chief collaborator spent much of his evening detonating tidy, penetrating bursts of bass, reminding everyone that this was a rap show foremost, and a terrific one.

Together, YG and Mustard are accepting challengers for rap album of the year after releasing YG’s “My Krazy Life” last month, a textbook example of how straightforward rhymes and uncomplicated beats can create the most fascinating friction. In a genre that valorizes both freshness and classicism, they’re sitting on a surplus of both.

Like “My Krazy Life,” Friday night’s performance was just about perfect, proving that the ease with which Mustard’s music has moved across American radio has everything to do with how elegantly it booms through the air.

Born Dijon McFarlane, the 23-year-old producer is a maximalist’s minimalist. He builds tracks out of classic 808 kablooey, synthetic handclaps and keyboard lines that could easily be tapped out with an index finger. But somehow, he whips that little recipe into something colossal, unpretentious, beautiful and functional, making his catalogue feel like hip-hop’s 21st century answer to Brutalist architecture. (Mustard’s style has been dubbed “ratchet,” a word that also suggests an exaggerated lack of couth in hip-hop, but at the end of the day, this is clean music to do dirty things to.)

He served as YG’s foil and his opening act Friday night, delivering a crowd-hyping set that blended songs from Jay Z and Washington’s own Shy Glizzy with his own trademark productions: 2 Chainz’s “I’m Different,” Ty Dolla $ign’s “Paranoid” and Tyga’s “Rack City,” a song so accessible that Justin Bieber covered it on his 2012 tour. Two years later, Mustard and the Biebs are reportedly working on new music together.

Perhaps those increasing demands on Mustard’s studio time explain why YG so rapidly stepped up from ordinary boaster to the savvy storyteller we hear on “My Krazy Life.” Raised in Compton — the same turf N.W.A. came roaring straight outta two years before YG and Mustard were even born — the 24-year-old rapper is following in the footsteps of his gangsta forerunners, rhyming about a life of frequent felonies, hard partying, big dreams and unshakable guilt.

“I can’t die, I got too much to live for,” he rapped during “I Just Wanna Party,” a song with a five-note piano riff that’s patently DJ Mustard. “I’m getting money, that’s what [expletive] rob and kill for.”

In addition to roughly following the narrative arc of “My Krazy Life,” the rapper’s entourage actually acted out a few of the album’s skits. Before “Meet the Flockers,” a jaw-dropping how-to lesson in home robbery, two guys in balaclavas tried to pry their way into a prop house intended to make the stage look like the block YG grew up on. It was chintzy, like something out of a high school play, but it felt transportive.

That’s because every syllable and every beat YG and Mustard meted out up there felt instantly and supremely confident. The hip-hop ethos is predicated on convincing the rest of the world that you’re the one standing on top. These guys knew they were.