British singer-songwriter Lapsley. (Alexander Waespi/ )

Imagine what Adele would sound like if she had dabbled with GarageBand instead of picking up the guitar, and you’re halfway to Lapsley. Like that global star before her, the English singer-songwriter born Holly Lapsley Fletcher released her first album at 19 and dazzles with a smoky voice that carries the weight of a life not yet lived. But that’s where the comparison ends.

On her debut album, “Long Way Home,” Lapsley sings mostly about teenage love — specifically heartbreak punctuated by moments of bliss — and her voice gets more vulnerable the higher the pitch. Perhaps that’s why she layers her voice with pitched-down doppelgängers in DIY duets, an androgynous communion that provides strength in numbers.

She certainly wasn’t alone on Monday night as she performed at a sold-out concert at U Street Music Hall. The performance — loud, powerful, intimate — was perfectly situated in the subterranean venue, and between Lapsley’s down-tempo grooves and the cold-colored lighting rig behind her, it felt like a London lounge in the near future.

Backed by a three-piece band, Lapsley glided through her growing discography. On her best songs, synths swell to wall-of-sound crescendos before being stripped away to reveal weeping keys ; a reverb-heavy, The XX-styled riff; or simply Lapsley’s voice. When the geometry of her lighting was replaced with a lone backlight, the latter was even more profound.

Although influenced by U.K. dance, the grooves of Lapsley’s music are almost surreptitious: Her songs move in slow motion and seem appropriate for only the most horizontal of dancing. When she changes the mood with something upbeat, like on the stadium-size ballad “Love Is Blind” and the Manhattan Transfer-sampling “Operator (He Doesn’t Call Me),” the feeling is pleasant but fleeting. The latter is a fun disco trifle but lyrics such as “Don’t put me on hold please” and “He doesn’t call me so put me through operator” don’t ring true when coming from a teenager in 2016.

Lapsley is still a few months away from her 20th birthday, but you wouldn’t know it from her command of the stage and the crowd. In her Scouse accent, she cracked jokes about indigestion, her tourmates (“boys smell”) and the “X-rated version” of her show, and kept the usually talkative U Hall crowd rapt.

After closing her set with the fan-favorite “Station,” Lapsley returned to the stage and encored with a sparse cover of Kate Bush’s “This Woman’s Work” and the “Long Way Home” highlight “Hurt Me,” which is a showcase of everything she does well. Over an understated groove, persistent melody and warped vocal samples, she anticipates heartbreak, singing, “So if you’re gonna hurt me, why don’t you hurt me a little bit more?” It’s a lyric that’s poignant whether you’re 19 or not.

Kelly is a freelance writer.