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.

"Without a Paddle," a slapstick comedy about three pals on a canoe trip in search of treasure, opened in second place.

After two strong weeks in limited release, the shark tale "Open Water" expanded nationwide and came in at No. 5 with $11.75 million.

"Exorcist: The Beginning," a prequel to the 1973 horror blockbuster "The Exorcist," stars Stellan Skarsgard 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. Skarsgard replaced 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 Skarsgard but replacing other cast members and tweaking the story.

Estimated ticket sales for Friday through Sunday at North American theaters, according to Exhibitor Relations Co. Inc.:

1. "Exorcist: The Beginning," $18.2 million.

2. "Without a Paddle," $13.7 million.

3. "Princess Diaries 2: Royal Engagement," $13.2 million.

4. "Alien vs. Predator," $12.5 million.

5. "Open Water," $11.75 million.

6. "Collateral," $10.5 million.

7. "The Bourne Supremacy," $6.6 million.

8. "The Manchurian Candidate," $4.2 million.

9. "The Village," $3.7 million.

10. "Garden State," $3.2 million.