NEW YORK (AP) — “Guardians of the Galaxy” became the summer’s top-grossing movie at the North American box office with a $17.6 million weekend that narrowly bested the young adult melodrama “If I Stay,” while the long-delayed “Sin City” sequel, “A Dame to Kill For” flopped.

With an estimated $17.6 million in its fourth weekend of release, the Marvel space adventure passed “Transformers: Age of Extinction” to become the summer’s biggest domestic hit with a cumulative total of $252 million. The film, released by Disney, was an unlikely August sensation (late summer is usually an afterthought in Hollywood’s lucrative summer season) that helped the box office rebound somewhat after big-budget sequels like “The Amazing Spider-Man 2″ and “How To Train Your Dragon 2″ failed to ignite the multiplexes. “This movie just couldn’t have come at a better time,” said Paul Dergarabedian, senior media analyst for box-office tracker Rentrak. “When we were really down and out in the summer box office — at one point down 20 percent from last year — ‘Guardians’ came along and injected life. What is surprising is that it was a film launched in August.”

The Warner Bros. tearjerker “If I Stay” failed to top the box office with a weekend haul of $16.4 million, according to studio estimates Sunday. In the film, a co-production between MGM and New Line Cinema, Chloe Grace Moretz stars as a teen in a coma after a car accident. It came in third place behind the reptile reboot “Teenage Mutant Ninja Turtles,” which made $16.8 million in its third weekend.

Dan Fellman, head of domestic distribution for Warner Bros. said the studio was pleased with the performance of “If I Stay” considering its $11 million production budget. Advance tracking on the film had forecast a box office-topping result, but tracking had also expected “Sin City: A Dame to Kill For” to open in the mid-teens. It made just $6.5 million.

“This is a complete miss,” said Erik Lomis, the Weinstein Co.’s distribution chief. “Obviously, we’re very, very disappointed in the numbers. We definitely did not see it coming in like this.”

The hurt was particularly acute, Lomis said, because it happened with a longtime Weinstein Co. collaborator, director Robert Rodriguez. He helmed the first “Sin City” film, which opened with $29.1 million in 2005 and made $159 million globally. But nine years is a long time to wait for a sequel, and clearly the novelty of the film’s digital adaptation of Frank Miller’s black-and-white graphic novel wore off with both moviegoers and critics.

The faith-based high school football film “When the Game Stands Tall” opened with $9.1 million for Sony.

Estimated ticket sales for Friday through Sunday at U.S. and Canadian theaters, according to Rentrak. Where available, latest international numbers are also included. Final domestic figures will be released on Monday.

1. “Guardians of the Galaxy,” $17.6 million.

2. “Teenage Mutant Ninja Turtles,” $16.8 million.

3. “If I Stay,” $16.4 million.

4. “Let’s Be Cops,” $11 million.

5. “When the Game Stands Tall,” $9.1 million.

6. “The Giver,” $6.7 million.

7. “The Expendables 3,” $6.6 million.

8. “Sin City: A Dame to Kill For,” $6.5 million.

9. “The Hundred-Foot Journey,” $5.6 million.

10. “Into the Storm,” $3.8 million.

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Universal and Focus are owned by NBCUniversal, a unit of Comcast Corp.; Sony, Columbia, Sony Screen Gems and Sony Pictures Classics are units of Sony Corp.; Paramount is owned by Viacom Inc.; Disney, Pixar and Marvel are owned by The Walt Disney Co.; Miramax is owned by Filmyard Holdings LLC; 20th Century Fox and Fox Searchlight are owned by 21st Century Fox; Warner Bros. and New Line are units of Time Warner Inc.; MGM is owned by a group of former creditors including Highland Capital, Anchorage Advisors and Carl Icahn; Lionsgate is owned by Lions Gate Entertainment Corp.; IFC is owned by AMC Networks Inc.; Rogue is owned by Relativity Media LLC.

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Follow AP Film Writer Jake Coyle on Twitter at: http://twitter.com/jakecoyleAP