TORONTO—Warner Bros. and Participant Media’s viral pandemic thriller Contagion successfully infiltrated the domestic box office with a $23.1 million debut, easily winning the weekend race.

Yet don’t forget The Help. The late-summer hit may have been bumped down to No. 2 after coming in No. 1 for 25 days in a row—the best showing since The Sixth Sense (35 days)–but it still scored a weekend take of $8.7 million for a new domestic total of $137.1 million.

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The performance of The Help and Steven Soderbergh‘s Contagion is a notable win for Participant Media, which co-financed and co-produced both titles (Contagion with Warner Bros., and The Help with DreamWorks). The socially minded production company–run by CEO Jim Berk and president Ricky Strauss–was founded by Jeff Skoll, who runs a separate foundation focusing on the five biggest threats facing the globe–one of them being pandemics.

Contagion, starring Matt Damon, Gwyneth Paltrow, Marion Cotillard, Jude Law, Laurence Fisburne, Kate Winslet and Bryan Cranston, is about as a team of CDC doctors, world health officials and citizens caught up in trying to stop a worldwide viral outbreak. The $60 million pic received a B- CinemaScore, with more than 80% of the audience over the age of 25.

“A wonderful director, a compelling storyline and a great marketing campaign and release date delivered a terrific result,” said Warner Bros. executive vp domestic distribution Jeff Goldstein.

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The big surprise of the weekend–stand-up comedy concert pic Kevin Hart: Laugh at My Pain, which grossed $2 million from only 97 AMC Theaters for a location average of $20,619, the best of any film this weekend.

But the news ranged from so-so to grim for the two other new entries. And overall, the film business is looking at one of the worst weekends of the year in terms of revenues, which are expected to top out at $77 million.

Lionsgate’s mixed martial arts drama Warrior, playing in 1,869 theaters, grossed a lower-than-expected $5.6 million in its opening frame to come in No. 3. At the same time, the film — starring Nick Nolte, Joel Edgerton and Tom Hardy – is a favorite of critics and drew an A CinemaScore from moviegoers, portending good word-of-mouth. Heading into the weekend, the movie was projected to gross $7 million to $8 million.

“We’re focusing on what lies ahead,” said David Spitz, executive vp distribution for Lionsgate, adding that the film scored the highest per theater average ($3,000) of any film in the top 10 besides Contagion ($7,180).

Warrior played heavily to males, who made up 66% of the audience, while 51% percent were under the age of 25.

Sony’s R-rated comedy Bucky Larson: Born to be a Star, produced by Adam Sandler‘s Happy Madison, was an all-out bomb, opening to only $1.5 million from 1,500 theaters to fall outside of the top 10—one of the worst studio openings in recent times. (Oddly, Bucky Larson received a B CinemaScore).

Sony said while Bucky Larson, starring Nick Swardson, Stephen Dorff and Christina Ricci, was made and marketed on a modest budget, the opening was clearly a disappointment. Sandler co-wrote the script with Allen Covert and Swardson.

Among holdovers, Focus Features and Miramax’s Helen Mirren thriller The Debt continued to impress in its second weekend, placing No. 4 and grossing an estimated $4.9 million for a cume of $22 million.

Focus president of distribution Jack Foley said The Debt’s ranking “speaks well of its strong hold in the marketplace. The film is popular and is showing good legs, especially in light of the competition this weekend.”

Sony’s Zoe Saldana action pic Colombiana came in at No. 5, grossing an estimated $4 million for a cume of $29.8 million in its third weekend. Fox’s Rise of the Planet of the Apes came in No. 6 in its sixth weekend, grossing an estimated $3.9 million and upping its domestic take to a pleasing $167.8 million.

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Shark Night 3D and Apollo 18 didn’t fare so well in their in their second weekends.

Distributed by Relativity on behalf of Incentive Filmed Entertainment and Sierra/Affinity, Shark Night fell 58% to an estimated $3.5 million for a domestic cume of $14.8 million; Apollo 18, from the Weinstein Co./Dimension Films, tumbled 67% to an estimated $2.9 million for a domestic total of $15 million.

The Weinstein Co. has had a tough time in recent weeks. Our Idiot Brother and Spy Kids: All the Time in the World in 4D, which came in No. 9 and No. 10 respectively over the weekend, also have underperformed.

DOMESTIC BOX OFFICE (Sept. 9-11)

Title/Distributor/Locations/Weekend Gross

1. Contagion (Warner Bros., 3,222): $23.1 Million 2. The Help (Disney, 2,935): $8.7 Million 3. Warrior (Lionsgate, 1869): $5.6 Million 4. The Debt (Focus, 1,872): $4.9 Million 5. Colombiana (Sony, 2,354): $4 Million 6. Rise of the Planet of the Apes (Fox, 2,887): $3.9 Million 7. Shark Night 3D (Relativity Media, 2,848): $3.5 Million 8. Apollo 18 (Weinstein Co., 3,330): $2.9 Million 9. Our Idiot Brother (Weinstein Co., 2,396): $2.8 Million 10. Spy Kids: All the Time in the World in 4D (Weinstein Co., 2,544): $2.5 Million

Source: Studios