By Dean Goodman

LOS ANGELES (Reuters) - In a surprising start to the fall movie-going season, the low-budget teen thriller "Swimfan" opened at No. 1, preventing the hit romantic comedy "My Big Fat Greek Wedding" from claiming the top spot in its 21st weekend of release.

According to studio estimates issued Sunday, "Swimfan" -- pitched as a "Fatal Attraction" for teen-agers -- grossed about $12.4 million for the three days beginning Sept. 6. It was followed by "Wedding" at $10.6 million, and the new Robert De Niro cop drama "City By The Sea" with $9.1 million.

After two consecutive weekends at No. 1, Mel Gibson's supernatural thriller "Signs," fell to No. 4 with $8.0 million.

"Wedding" has arguably been the biggest hit of the year, costing just $5 million to make and hauling in $97 million to date. It opened in limited release last April and relied on positive word-of-mouth as it slowly added theaters. It moved up to the No. 2 slot last weekend, narrowly behind "Signs," and was expected to grab the crown this weekend.

But most people did not bank on "Swimfan," which did not even screen in advance for critics, a measure usually taken when a studio wants to limit possible bad word-of-mouth.

"GREAT LITTLE SURPRISE"

"Swimfan," which reportedly cost less than $10 million to make, was distributed by Twentieth Century Fox, a unit of News Corp.'s Fox Entertainment Group Inc.

Going into the weekend, Fox would have been happy with an $8 million opening, said Rick Myerson, the studio's executive VP of distribution.

"It's one of those great little surprises," Myerson said of the eventual figure. It is notoriously hard to predict how well teen films will do at the box office.

Erika Christensen plays a girl obsessed with the school's swimming champion, played by Jesse Bradford. Shiri Appleby plays his girlfriend. Australian John Polson directed.

As is usually the case with thrillers, females made up the majority of the young audience, about 60 percent, Myerson said. The young demographic has not been targeted with a movie since "XXX" opened on Aug. 9 followed by "Blue Crush" a week later, he noted.

One person who was not surprised by how well "Swimfan" did was Paul Brooks, president of Gold Circle Films, one of the backers of "My Big Fat Greek Wedding." Brooks said his film enjoyed an astonishing weekend -- its per-screen average of $6,249 was easily the highest in the top 10 -- and has yet to suffer any attrition.

He hoped the movie would eventually surpass the $140 million total of the most successful independent movie in history, "The Blair Witch Project."

"Wedding" stars Nia Vardalos as a frumpy spinster who causes chaos in her proud Greek-American family when she becomes engaged to a WASP. It was released by IFC Films, a unit of Rainbow Media Holdings Inc., which is majority owned by Cablevision Systems Corp.

DE NIRO AT "SEA"

"City By the Sea" stars De Niro as a veteran New York City detective who leads a murder investigation in which his estranged son (James Franco) is the chief suspect. It was directed by Briton Michael Caton-Jones directed.

Warner Bros. Pictures, a unit of AOL Time Warner Inc. , distributed the film for a fee on behalf of privately held producer Franchise Pictures. WB distribution president Dan Fellman said he was pleased with the opening, and he predicted it would be profitable for Franchise. It reportedly cost under $40 million to produce.

The film skewed older: 70 percent of the audience was aged over 30, and the gender mix was evenly split, Fellman said.

Gibson's "Signs," from writer/producer/director M. Night Shyamalan, has now grossed $205.8 million, becoming the fourth-highest grossing film of the year. It was released by Touchstone Pictures, a unit of Walt Disney Co.

The Vin Diesel action movie "XXX" fell two places to No. 5 in its fifth weekend as its total rose to $131 million. It was released by Sony Corp ( news - web sites).'s Columbia Pictures, which also snagged the No. 9 spot with an unusual double bill of summer hits "Spider-Man" and "Men in Black II." The combo grossed $2.0 million. A studio spokesman said the double-header was designed to lay the groundwork for the films' home video release in October and November, respectively.

The top 12 films grossed a modest $61 million, about even with the year-ago weekend, but off 14 percent from last weekend, according to tracking firm Exhibitor Relations.

With the prime summer season over and the studios preparing their end-of-year slates, September traditionally marks a lackluster time at the box office. New releases next weekend include the Tom Green comedy "Stealing Harvard" and the Ice Cube comedy "Barbershop."

Reuters/Variety

The top movies in North America -- September 6-8

LOS ANGELES (Reuters) - Following are the final data for the top 10 movies at the North American box office during the September 6-8 weekend, according to studio figures released Monday by Exhibitor Relations Co. Inc.

Title Gross

1. Swimfan .......... $11,326,601

BOX OFFICE SO FAR: $11,326,601

2. My Big Fat Greek Wedding .......... $10,372,316

BOX OFFICE SO FAR: $95,824,732

3. City By The Sea .......... $8,935,426

BOX OFFICE SO FAR: $8,935,426

4. Signs .......... $7,851,871

BOX OFFICE SO FAR: $205,696,958

5. XXX .......... $5,206,740

BOX OFFICE SO FAR: $130,708,185

6. Spy Kids 2 .......... $3,020,007

BOX OFFICE SO FAR: $73,936,549

7. Austin Powers in Goldmember .......... $2,721,316

BOX OFFICE SO FAR: $207,051,562

8. Feardotcom .......... $2,352,359

BOX OFFICE SO FAR: $10,545,479

9. Spider-Man/Men in Black II .......... $2,111,862

BOX OFFICE SO FAR: $2,111,862

10. Blue Crush .......... $1,878,325

BOX OFFICE SO FAR: $37,296,385

Reuters/Variety

John L.:  It was a fairly tame weekend at the box office but Swimfan's top spot appearance is no surprise since its add campaign was pretty good and it set up the premise as a young Fatal Attraction.  The reason it did not open huge is because the title is so stupid.  I sat through this flick so more later.  No one knows what a City by the Sea is and Robert Deniro's name alone rarely puts a butt in the seat.  Playing another cop makes it seem too predictable to the casual movie goer.  The Greeks are ruling it all around and has become the success story of the year.  Due to lateness, only a mini review of Swimfan will be posted.

SWIMFAN - MINI REVIEW

Movies are funny.  Only in movies can there be very hot women insisting on having sex with other guys.  What guy doesn't dream about being the object of a girl's obsession.  Oh the horror. Jesse Bradford plays Ben Cronin, star swimmer for the local high school.  He is on his way to a full college scholarship for his athleticism and he has a beautiful girlfriend, Amy (Shiri Appleby) who supports him.  Life is nearly perfect until Ben bumps into Madison.  For some reason she is a psychopath who becomes obsessed with Ben.  She will do anything to make him his lover.  This plot has been very popular the last 15 years or so in movies about the female stalker who believes if she can't have him noone will.  Glenn Close is the archetype for this character and after sitting through Swimfan she has nothing to worry about in terms of crazy bitch competition.  Erika Christensen plays Madison and is just okay in this underwritten role.  She is never given anything more kooky than sending some very unsexy email photos.  Her motivations are never made clear and when the movie is over, you will forget you sat through it.  Jesse Bradford is lost here and just has to act nervous everytime Madison gets too close to his real girlfriend.  This movie had one of the better previews of the last few months, but it also showed you every little thing Madison did to get under Cronin's skin.  The pool sex, the meeting of the mom, the email, the steroids, the car accident, and the kidnapping of the girlfriend.  Watch that, and you will have seen everything there is to see in the movie.   Nothing extra.  I was very disappointed.  Final Review:  5 out of 10; 2 stars; C; thumbs down.  There was no point to any of this.

The rest of the top 10 in 10 will return in a few weeks as I try to catch up.  Bye for now.