Boosted by international market growth and new fans brought in by recent films, 'Thor: The Dark World' hammered the competition at the box office this weekend. The second film in the God of Thunder franchise from Walt Disney Co. DIS +2.13% 's Marvel Studios grossed an estimated $86.1 million in North America, opening domestically after an international rollout that has brought its world-wide total to $327 million.

While the movie's domestic gross was impressive-and an improvement of more than $20 million on the original 'Thor' opening in May 2011-it was the international haul that seemed mythic. In 12 days, the movie's overseas gross has collected about 90% of the original 'Thor' international gross of $268 million.

Franchise sequels typically perform better than the original movie, in part because new audiences can discover the film in the years between releases. In Marvel's case, sequels like 'Thor: The Dark World' benefit from cross-promotion that comes with having the Thor character in hits like 'The Avengers,' which brought together multiple Marvel superheroes and grossed $1.5 billion world-wide last year.

The improvement in overseas figures also comes from staggering growth in some key international markets. In China, where thousands of new screens are added each year in response to seemingly insatiable consumer demand, the $19.6 million openingweekend gross of the Thor sequel exceeded the gross for the entire Chinese theatrical run of the original.

'The internationallandscape is growing at an extraordinary clip,' said Dave Hollis, Disney's executive vice president in charge of distribution.

Domestically, 'Thor: The Dark World' became the first Marvel release to perform better on Saturday than on Friday, Mr. Hollis said. Weekend releases of Superhero movies are typically frontloaded by super fans who want to see the movie on its first day of release or at a late Thursday evening screening. The improvement in Saturday ticket sales signals an uptick in interest for the movie from families, who made up about 21% of the openingweekend audience, Mr. Hollis said.

'The brand has done well to redefine itself as available to everyone,' he said.

IMAX screens generated $5.3 million in ticket sales for the movie, which was scheduled to be shown on the large-format screens last Monday so it could split the schedule with the underperforming 'Ender's Game' from Lions Gate Entertainment Corp.'s Summit Entertainment unit.

The performance caps a busy week for Marvel. On Thursday, Disney and Netflix Inc. announced the streaming service had ordered four 13-episode live-action superhero series featuring the Marvel characters Daredevil, Jessica Jones, Iron Fist and Luke Cage.