* Disney is already planning a sequel to blockbuster film
* New Johnny Depp horror film 'Dark Shadows' trounced
LOS ANGELES, May 13 (Reuters) - "The Avengers," the smash hit movie about Marvel superheroes who team up to save the Earth, crushed competitors for a second weekend with a record $103.2 million in U.S. and Canadian ticket sales and was poised to top $1 billion worldwide, studio estimates showed on Sunday.
After posting the highest domestic box office debut in history last weekend, "Avengers" set another record by easily topping the $75.6 million "Avatar" pulled in during its second weekend in 2009, making "Avengers" the first movie to exceed $100 million in its second weekend.
"Avengers" has now racked up a staggering $628.9 million internationally since opening overseas on April 25, distributor Walt Disney Co said, positioning it to break the $1 billion threshold after just 19 days.
"We're obviously thrilled," said Robert Iger, Disney's Chairman and CEO in a statement.
"You can never anticipate this kind of success," echoed Dave Hollis, executive vice president for motion picture distribution. "It's a staggering result."
Its success owed in large part to "a story that delivers on every level, to every segment of the audience," he added.
The big-budget 3D flick - the first of Hollywood's lucrative summer season - unites Iron Man, Black Widow, Captain America and other Marvel comic book heroes in a fight against a villain determined to destroy the planet. Disney announced this week it is planning an "Avengers" sequel.
The movie took in $207.4 million at North American (U.S. and Canadian) theaters over its opening weekend, helping improve the performance of the studio, which earlier stumbled at box offices with its big-budget release "John Carter."
"Avengers" mania overwhelmed new horror comedy "Dark Shadows," according to studio estimates compiled by Reuters. "Dark Shadows" pulled in an estimated $28.8 million from Friday through Sunday at domestic theaters.
The latest collaboration between actor Johnny Depp and director Tim Burton, the $100 million "Dark Shadows" is based on the cult TV soap opera that ran from 1966 to 1971 about vampires, werewolves and witches living in a ghostly countryside manor. Michelle Pfeiffer and Helena Bonham Carter also star.
Studio executives said the total was in line with expectations of about $30 million.
"We're hoping to leg it out over the next few weeks," said Dan Fellman, president of theatrical distribution for Warner Bros., referring to films developing "legs" and performing well for a period in the weeks after opening.
Fellman noted that big May films coming up were not really competing for the same audience as "Dark Shadows," which drew more than 50 percent of its opening weekend audience from viewers 35 and older.
"The audiences are applauding," he said, adding "There's a magic and chemistry that Tim Burton and Johnny Depp have had over the years, and we're hoping that will continue as we approach" the lucrative Memorial Day period.
"We opened extremely well internationally," with $36.7 million, Fellman noted.
In third place, romantic comedy "Think Like a Man" grossed $6.3 million during its fourth weekend in theaters.
Teen survival drama "The Hunger Games," the year's biggest movie before "Avengers" came on the scene, finished the weekend in fourth place with $4.4 million.
Fifth place belonged to love story "The Lucky One," which took in $4 million, with animated family film "The Pirates! Band of Misfits" coming in sixth at $3.2 million.
Warner Bros., a unit of Time Warner Inc, released "Dark Shadows" and "The Lucky One." "Think Like a Man" and "Pirates" were distributed by Sony Corp's Sony Pictures studio. Lions Gate Entertainment Corp released "Hunger Games."