Barry Jenkins’ “Moonlight” — not, as it turned out, “La La Land” — won best picture at the Academy Awards in a historic Oscar upset and an unprecedented fiasco that saw one winner swapped for another while the “La La Land” producers were in midspeech.

Presenters Warren Beatty and Faye Dunaway apparently took the wrong envelope — the one for best-actress winner Emma Stone — onto the stage. When they realized the mistake, representatives for ballot tabulators Pricewaterhouse Coopers raced onstage to stop the acceptance speech.

But backstage, Stone said she was holding her envelope at the time. “I think everyone’s in a state of confusion still,” said Stone. Later the actress, who pledged her deep love of “Moonlight,” added, “Is that the craziest Oscar moment of all time? Cool!”

It was, nevertheless, a shocking upset considering that “La La Land” came in with 14 nominations, a record that tied it with “Titanic” and “All About Eve.”

Barry Jenkins’ tender, bathed-in-blue coming-of-age drama, made for just $1.5 million, is an unusually small Oscar winner. Having made just over $22 million as of Sunday at the box office, it’s one of the lowest-grossing best-picture winners ever.

“Even in my dreams this cannot be true,” said an astonished Jenkins once he reached the stage.

Host Jimmy Kimmel had come forward to inform the cast that “Moonlight” had indeed won, showing the inside of the envelope as proof.

“I knew I would screw this up,” said Kimmel, a first-time host. “I promise to never come back.”

Producer Jordan Horwitz then graciously passed his statue to the “Moonlight” producers.

Up until the chaotic end, the telecast had seesawed between jabs at Donald Trump and passionate arguments for inclusivity, with awards going to “La La Land,” “Moonlight” and “Manchester by the Sea.”

Damien Chazelle’s celebrated musical “La La Land” took a while to start cleaning up. But as the night went on, its haul began piling up, winning for cinematography, production, score, song (“City of Stars”) and best actress for Emma Stone. Chazelle, the 32-year-old filmmaker, also became the youngest to win best director.

“This was a movie about love, and I was, luckily enough, to fall in love while making it,” said Chazelle, speaking about his girlfriend and Oscars date, Olivia Hamilton.

Barry Jenkins, the writer-director of “Moonlight,” and Tarell Alvin McCraney, who wrote the play it was based on, won for adapted screenplay. “All you people out there who feel like there isn’t a mirror out there for you, the academy has your back, the ACLU has your back and for the next four years we will not leave you alone, we will not forget you,” said Jenkins.

Kenneth Lonergan, the New York playwright whose last film (“Margaret”) was beset by lawsuits and conflict, won best original screenplay for “Manchester by the Sea.” “I love the movies. I love being part of the movies,” said Lonergan, who then thanked his star. “Thank you, Casey Affleck, Casey Affleck, Casey Affleck.”

Shortly later Affleck, in one of the night’s most closely watched categories, won best actor — his first Oscar — for his soulful, grief-filled performance in “Manchester.”

Affleck and Denzel Washington (“Fences”) were seen as neck-and-neck in the category. An admittedly “dumbfounded” Affleck looked shocked when his name was read.

“Man, I wish I had something bigger and more meaningful to say,” said Affleck, who hugged his more famous brother, Ben, before taking the stage.

The show kicked off with Justin Timberlake dancing down the Dolby Theatre aisles, singing his ebullient song “Can’t Stop the Feeling,” from the animated film “Trolls.”

It was an early cue that the Oscars would steer, at least in part, toward festiveness rather than heavy-handedness. Protests, boycotts and rallies have swirled ahead of Sunday night’s Oscars. But host Kimmel, in his opening monologue, quickly acknowledged that he “was not that guy” to heal a divided America.

But he still, pointedly, led a standing ovation for the “overrated” Meryl Streep. He later tweaked the president by tweeting to him on air, including telling him that Streep “says hi.”

The wins for Davis, who co-starred in Denzel Washington’s August Wilson adaptation “Fences,” and Mahershala Ali, the “Moonlight” co-star who won for best supporting actor, were both widely expected. Their awards marked the first time in more than a decade that multiple Oscar acting honors went to black actors.

The nominees follow efforts by Academy of Motions Pictures Arts and Sciences President Cheryl Boone Isaacs to diversify the membership of the largely white male film academy. “Tonight is proof that art has no borders, no single language and does not belong to a single faith,” Isaacs said.