Billie Eilish is comfortable onstage. Maybe too comfortable.

During her nearly two-hour set at Chase Center on Tuesday, March 29, which marked her San Francisco arena debut nearly two years after she was originally set to perform there, the 20-year-old phenom took a moment to admit that she had forgotten to brush her teeth. And her breath stank.

But who could blame her? It’s been a whirlwind few days for the pop singer, whose “No Time to Die” track was named best original song at the Academy Awards just two days prior.

“This is my first show back since, umm, I won an Oscar,” she coyly told her screaming fans. “It has been such a chaotic week, I can’t even tell you.”

Warning: The following video contains explicit language

Here’s@billieeilishacknowledging her#Oscarswinpic.twitter.com/bCL17jKSKy

— Mariecar Mendoza (@SFMarMendoza)March 30, 2022

At another point in the show, Eilish sat down on a stool and encouraged her fans to lift up their signs so she could read them aloud. After a blood-pumping opening set by rapper and singer-songwriter Duckwrth, who started his music career in San Francisco after dropping out of the Academy of Art University, Eilish, dressed in her signature baggy T-shirt and shorts ensemble, emerged from under the stage. From that moment on, she displayed a magnetism and clear command of the sold-out crowd that is unusual to see in a young artist. Standing on a minimalist set with no one else except brother Finneas on the guitar and keys and Andrew Marshall on drums, she delivered personality and a contagious yet casual energy.

All eyes were on Eilish, and Eilish, ever the performer, was more than happy to oblige, telling her audience what not to do (“be an asshole” and “judge others”) and what to do (“have a good time”). It’s almost as if she were born to do this.

Still, there were some moments when it seemed like the audience wasn’t meant to be there at all. When Finneas joined her at center stage to lead the crowd in singing “Happy Birthday” to their mother, Maggie Baird, who was in attendance Tuesday, it felt for a moment that the crowd was intruding on a family occasion.

In “Your Power,” Eilish, for the most part, sang to herself and her brother and never once glanced at the audience. It was a sight to behold, this strange juxtaposition of intimacy and distance. With the exception of a spotlight on the sibling duo, the arena was dark, speckled with smartphone flashlights that evoked a starry night. It was as if no one was watching them at all. The world was just the two of them, brother and sister, acoustic guitars in arms, casually jamming under a starlit sky, singing about the people who abuse their power and take advantage of young women. When they sing together, Finneas’ voice is gentle, supporting that of his younger sister.

Eilish’s addition of “No Time to Die” to the set list proved to be an excellent choice. Over the course of the haunting Oscar-winning ballad, images from the latest James Bond film played behind her as her voice soared through the climax of the song.

Those intimate moments, though few, were most precious, and added a necessary contrasting dimension to Eilish’s overall high-energy performance.

Digital projections sometimes helped mitigate whiplash from transitions between songs with dissimilar energies. But just as often, they did the opposite, from scary images of a writhing snake and a giant spider to a sparse highway scene. Eilish’s stage persona changed to match the song’s mood just as quickly, sometimes unsettlingly so.

By far the most jarring moment of the evening, however, came toward the end, when Eilish revisited several of her songs from her 2019 “When We All Fall Asleep, Where Do We Go?” album. Eilish went from the upbeat “All Good Girls Go to Hell,” coupled with a video montage demonstrating the destructive impact of humankind on the environment, to the dark, poignant “Everything I Wanted.”

“Thought I could fly/ So I stepped off the Golden/ Nobody cried/ Nobody even noticed,” Eilish sang.

事实上,一些观众似乎注意到——或者care — that they were cheerfully jumping along to a song about suicide on the nearby Golden Gate Bridge in an arena overlooking the San Francisco Bay.

“If I knew it all then, would I do it again?/ Would I do it again?/ If they knew what they said would go straight to my head/ What would they say instead?” she continued, leading the crowd to wave their arms. Standing in the aisle, a mother, carrying a young child, bounced along to the lyrics.

Occasionally, Eilish’s more whispered songs were swallowed up by the pounding bass and cheering fans. When Eilish was lifted by a crane into the back rows for “Not My Responsibility,” “Bellyache” and “Ocean Eyes,” for instance, her voice became muddled.

Eilish finished off the evening with fan favorite “Bad Guy,” which had the audience jumping up and down with her, and “Happier Than Ever,” the title of her sophomore album and tour.

“Before I go, I just want to say thanks,” she said, shortly before sliding down the large ramp to center stage. “Thank you for giving a s–!”

Billie Eilish: “Happier Than Ever” tour:7:30 p.m. Wednesday, March 30. $146 and up. Golden 1 Center, 500 David J. Stern Walk, Sacramento.www.billieeilish.com