Los Angeles ? Arnold Schwarzenegger as an avenging firefighter hunting terrorists proved a solid attraction, though not quite a must-see movie.

Schwarzenegger’s “Collateral Damage,” delayed four months because of the Sept. 11 terrorist attacks, opened as the top weekend movie with $15.2 million in ticket sales, according to studio estimates Sunday.

It was Schwarzenegger’s first No. 1 opening since “Batman & Robin” in 1997, but the receipts were so-so compared with that film’s $42.9 million debut or the $31.8 million premiere of “Terminator 2: Judgment Day” in 1991.

The family flick “Big Fat Liar,” starring Frankie Muniz of “Malcolm in the Middle” as a teen out to prove a Hollywood producer stole his movie idea, debuted in second place with $11.7 million. And the remake of “Rollerball,” starring Chris Klein, LL Cool J and Rebecca Romijn-Stamos, opened at No. 3 with $9 million.

The box office was down overall, with the top 12 movies grossing $83.8 million, a 22 percent drop from the same weekend last year. But that was the weekend “Hannibal” debuted with a whopping $58 million.

The Winter Olympics, which opened Friday, probably kept some movie-goers at home this weekend, said Paul Dergarabedian, president of Exhibitor Relations, which tracks the box office.

In addition, “Collateral Damage” and “Big Fat Liar” were coolly received by critics, and reviewers trashed “Rollerball.”

Playing in 2,824 theaters, “Collateral Damage” averaged a decent though unspectacular $5,375 a location. “Big Fat Liar” averaged $4,641 in 2,521 theaters, and “Rollerball” did $3,267 at 2,762 sites.

“Collectively, the three new films were the most attractive to movie-goers, but people weren’t beating down the doors to see any of these movies,” Dergarabedian said.

Originally scheduled for release last October, “Collateral Damage” was put on hold after Sept. 11. Schwarzenegger and distributor Warner Bros. felt audiences would not have the stomach to see a fireman hunt terrorists, especially given the heroism of New York City firefighters killed in the World Trade Center attack.

Now that time has passed, the firefighter connection may have heightened the film’s appeal.

“I’m not sure of that. It’s hard to pick that up in our research. But based on the solid performance of the movie, you have to think that had some effect,” said Warner head of distribution Dan Fellman.

“Monster’s Ball,” a death row drama expected to earn an Oscar nomination Tuesday for Halle Berry, expanded from a handful of screens to 341 theaters, taking in $2.3 million for a $6,745 average. The film has grossed $3.9 million since opening in December to qualify for the Oscars.

That movie and other likely nominees, including “Black Hawk Down,” “A Beautiful Mind” and “In the Bedroom,” should get a box-office boost from the Oscar attention leading up to the awards ceremony March 24.

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

1. “Collateral Damage,” $15.2 million.

2. “Big Fat Liar,” $11.7 million.

3. “Rollerball,” $9 million.

4. “Black Hawk Down,” $8 million.

5. “Snow Dogs,” $6.7 million.

6. “The Count of Monte Cristo,” $6.3 million.

7. “A Beautiful Mind,” $5.8 million.

8. “A Walk to Remember,” $5.77 million.

9. “The Mothman Prophecies,” $4.9 million.

10. “I Am Sam,” $4.5 million.