* 'Contagion' No. 1 with $23.1 mln domestically
* 'The Help' falls to second place
* New drama 'Warrior' third, 'Bucky Larson' bombs (Adds details on top 5 films, quotes)
LOS ANGELES, Sept 11 (Reuters) - "Contagion" gripped filmgoers as the thriller about the race to contain a deadly virus took hold of the top spot at the domestic box office and knocked hit drama "The Help" to second place.
"Contagion" brought in an estimated $23.1 million at U.S. and Canadian theaters over its first three days, distributor Warner Bros. said on Sunday. Six international markets added another $2.1 million.
Directed by Steven Soderbergh, the film tells the story of a fast-spreading killer virus and scientists' efforts to stop it as the body count rises. The movie features an all-star cast that includes Matt Damon, Gwyneth Paltrow, Kate Winslet, Laurence Fishburne and Jude Law.
The film beat studio expectations by telling "a tough story in a provocative way. There is nothing more icky than this," said Jeff Goldstein, executive vice president of domestic distribution for Warner Bros.
Audiences polled by CinemaScore gave the movie a B- rating on average.
"The Help," a critics and audience favorite about black maids who speak out about white employers in civil rights-era Mississippi, slipped to second place after three straight weeks as the box-office leader. The film soaked up $8.7 million, pushing up its domestic receipts to $137.1 million since the book adaptation hit theaters five weeks ago.
"Warrior," a new drama about two brothers who battle for victory and redemption in a mixed-martial arts tournament, finished third with a disappointing $5.6 million. The brothers, a war veteran played by Tom Hardy and a high-school teacher and father played by Joel Edgerton, face wounds from the past as their estranged father, portrayed Nick Nolte, works as one of their coaches.
The film earned an A from audiences polled by CinemaScore and positive reviews from critics.
"We're going to continue to fight. The film is an underdog story and this is an underdog movie," said David Spitz, head of domestic distribution for Lionsgate (LGF.N), the studio that released the film.
'BUCKY LARSON' FLOPS
The No. 4 movie domestically was spy thriller "The Debt" with $4.9 million over its second weekend. Action movie "Colombiana," starring Zoe Saldana as an assassin seeking revenge, landed fifth with $4.0 million.
Comedy "Bucky Larson: Born to Be a Star" was a box-office bomb. Panned by critics, the film about a Midwestern kid who moves to Hollywood to become a porn star brought in $1.5 million in North American receipts and failed to crack the weekend's top 10. "While the movie was made on a very modest budget, it didn't work out the way we hoped," Sony spokesman Steve Elzer said.
Warner Bros., a unit of Time Warner Inc (TWX.N), released "Contagion." Sony Corp (SNE.N) (6758.T) unit Columbia Pictures released "Colombiana" and "Bucky Larson."
"The Help" was produced by DreamWorks and distributed by Walt Disney Co. (DIS.N). Focus Features, a unit of Comcast Corp's (CMCSA.O) Universal Pictures, released "The Debt." (Reporting by Lisa Richwine; Editing by Eric Beech)