Rami Malek has won the Oscar for best actor at the 91st Academy Awards for his role as Freddie Mercury in Bohemian Rhapsody.

Malek defeated a strong field, including Christian Bale as Dick Cheney in Vice and Bradley Cooper as musician Jack Maine in A Star Is Born. Malek was the favourite to win, however, having previously picked up a string of awards for the role including best actor from the Baftas and Screen Actors Guild and best actor (drama) at the Golden Globes.

Bohemian Rhapsody is a biopic of British rock act Queen, with a focus on its lead singer, Mercury, who died in 1991 from Aids-related illness. Prior to Bohemian Rhapsody, Malek was best known for his role in the award-winning TV series Mr Robot, in which he played hacker Elliot Alderson. Malek’s performance in Bohemian Rhapsody was described as “electric” by the Observer critic Simran Hans, and as “a feat of impersonation” by the Guardian’s Steve Rose.

The film has been a significant box-office success, despite a troubled production process. Sacha Baron Cohen was originally due to play Mercury, but dropped out after disagreements with Queen’s surviving band members. Director Bryan Singer was fired during shooting and replaced by Dexter Fletcher; however Singer retains sole credit due to union regulations. Singer was subsequently accused of sexual misconduct and underage sex in a magazine article, which he denies as a “homophobic smear”. In February, Malek suggested it had been difficult working with Singer saying: “My situation with Bryan, it was not pleasant, not at all.”

In his speech, Malek paid tribute to his parents, saying of his mother, who was in the auditorium “I love you, lady” and expressing the belief that his father would be “looking down on me right now”.

Although he said of the film’s cast and crew “I love you, you are my equals, you are my betters”, he did not mention Singer by name. He singled out co-star Lucy Boyton, with whom he is now in a relationship, and the band Queen, saying: “I may not have been the obvious choice [to play Freddie Mercury] but I guess it worked out.”

Malek also said that the acclaim and enormous audience the film had found indicated the appetite for stories about minorities. “A film about a gay man, an immigrant, who lived his life unapologetically as himself.”