LOS ANGELES – God vs. Satan cast out space creatures at the box office.

Demon thriller “Exorcist: The Beginning” debuted as the no. 1 weekend movie with $18.2 million, displacing “Alien vs. Predator,” which tumbled to no. 4 with $12.5 million, studio estimates showed yesterday.

“Without a Paddle,” a slapstick comedy about three pals on a canoe trip in search of treasure, opened in second place with $13.7 million.

After two strong weeks in limited release, the shark tale “Open Water” expanded nationwide and came in at no. 5 with $11.75 million, lifting its domestic total to $14.8 million.

Another popular limited-release flick, Zach Braff’s romantic comedy “Garden State,” also went into fairly wide release, taking the no. 10 spot with $3.2 million and pushing its total to $6.7 million.

“Exorcist: The Beginning,” a prequel to the 1973 horror blockbuster “The Exorcist,” stars Stellan Skarsgaard as the priest of the original movie in his first encounter with the devil in late 1940s Africa.

Original star Liam Neeson departed after director John Frankenheimer dropped out. Mr. Skarsgaard replaced Mr. Neeson and filmed the movie with director Paul Schrader, whose version was shelved by the producers as not scary enough.

Director Renny Harlin shot a second version, keeping Mr. Skarsgaard but replacing other cast members and tweaking the story.

“We had so much baggage from the fact that two movies were shot and so many things had happened along the way. It created in the press the kind of perception that this is a troubled production,” Mr. Harlin said. “While really, the shooting of this version was extremely smooth.”

Though trashed by critics, Mr. Harlin’s movie had solid appeal for horror fans, who typically turn out in droves on opening weekend.

“You can always count on horror films to do well,” said the president of box-office tracker Exhibitor Relations, Paul Dergarabedian. “There’s just this built-in audience base that loves this genre.”

The movie could follow the same path as “Alien vs. Predator,” whose $12.5 million second weekend was down a steep 67% from its opening gross.

Like “Alien vs. Predator” revenues, receipts for “Exorcist” dropped sharply from Friday to Saturday, a sign of poor word of mouth from early viewers. Most new movies do more business on their first Saturday than on Friday.

“Without a Paddle,” starring Seth Green, Matthew Lillard and Dax Shepard, played largely to the 21-andyounger crowd but, surprisingly, drew slightly more females than males. Distributor Paramount had expected the buddy comedy to score a mostly male audience.

The movie was another genre flick unaffected by its flogging from critics.

“Anytime you have sort of a lampoon comedy like this, this audience doesn’t pay much attention to reviews,” said Paramount’s head of distribution Wayne Lewellen.

In limited release, actor Stephen Fry’s directing debut on the Jazz-age satire “Bright Young Things” premiered strongly with $53,500 in three theaters. Based on Evelyn Waugh’s novel “Vile Bodies,” the film’s ensemble cast includes Emily Mortimer, Dan Aykroyd, Jim Broadbent, and Peter O’Toole.