Los Angeles ? The fright flick “The Last Exorcism” and the heist thriller “Takers” were in a photo finish for the top spot at the weekend box office, according to studio estimates Sunday.

Lionsgate’s “The Last Exorcism” had a thin lead with a $21.3 million debut, closely followed by Sony’s “Takers” with a $21 million opening. They were close enough that rankings could change after final numbers are released today.

After two weekends in the No. 1 spot, Lionsgate’s “The Expendables” slipped to third place with $9.5 million, raising its total to $82 million.

Playing in narrower release, a 3-D special edition of “Avatar” pulled in $4 million, lifting the sci-fi sensation’s domestic total to $753.8 million. The new version of the 20th Century Fox blockbuster adds nine minutes of footage.

Estimated ticket sales for Friday through Sunday at U.S. and Canadian theaters, according to Hollywood .com.

1. “The Last Exorcism,” $21.3 million.

2. “Takers,” $21 million.

3. “The Expendables,” $9.5 million.

4. “Eat Pray Love,” $7 million.

5. “The Other Guys,” $6.6 million.

6. “Vampires Suck,” $5.3 million.

7. “Inception,” $5.1 million.

8. “Nanny McPhee Returns,” $4.74 million

9. “The Switch,” $4.7 million.

10. “Piranha 3D,” $4.3 million.