Green Book sprang a surprise by winning the award for best picture at this year’s ceremony in Los Angeles.
Olivia Colman defied the odds to scoop an Oscar for best actress for her role in The Favourite and charmed viewers with a funny and tearful speech.
Green Book won three awards in total, including best picture, which had been expected to go to Netflix’s Roma.
Bohemian Rhapsody won the most awards in total with four, while Roma and Black Panther also won three each.
Olivia Colman, who started out as a sidekick in TV sitcoms like Peep Show, was in shock when her name was called.
Glenn Close had been the firm favorite for her role in The Wife – and now has the unenviable record of seven nominations without a win.
Olivia Colman is the first British actress to win the prize since Kate Winslet in 2009.
The four awards for Bohemian Rhapsody, the authorized biopic of Queen and Freddie Mercury, included best actor for Rami Malek, who won rave reviews for playing the late singer.
It was later reported that Rami Malek, 37, fell off the stage after the ceremony concluded and had to be helped into a seat by security staff.
He was reportedly attended to by paramedics, though he made no reference to the incident later when he spoke to reporters backstage.
Mahershala Ali won his second best supporting actor Oscar in three years. He won for Moonlight in 2017 and has now won for playing jazz pianist Don Shirley in Green Book.
Green Book tells the story of Don Shirley’s tour to the racially segregated US Deep South in the 1960s, but its chances had been thought to have been dented by a series of controversies.
Meanwhile, a tearful Regina King won best supporting actress for If Beale Street Could Talk, from what was her first Oscar nomination.
Richard E Grant, Rachel Weisz and Christian Bale lost out on the acting awards.
However, Mark Ronson shared the best song award with Lady Gaga, among others.
Paul Lambert and Tristan Myles shared the prize for best visual effects with two American colleagues for creating the rocket-rattling effects on First Man, about the first Moon landing.
Key crew members on Bohemian Rhapsody won the two sound awards.
The Oscars failed to find a main host this year after comedian Kevin Hart pulled out following a row about old homophobic tweets.
Instead of having the traditional opening monologue, Tina Fey, Maya Rudolph and Amy Poehler appeared to introduce the show as well as presenting the first award.
“We are not your hosts this year but if we had hosted, it probably would have gone like this,” Tina Fey said – before the trio launched into a sketch poking fun at some of the nominees, which is one of the host’s usual jobs.
The ceremony continued to rely on a procession of stars presenting individual awards.
However, it didn’t obviously suffer from the lack of an overarching host, and it helped the event move along.
Queen, fronted by singer Adam Lambert, had opened the ceremony with a bombastic medley of We Will Rock You and We Are the Champions as A-listers waved and clapped along in their seats.