Seven decades after Captain America first socked Adolf Hitler in the kisser, the star-spangled, super-serummed hero still packs a mighty commercial punch.

“Captain America: The First Avenger” topped the weekend box office by grossing $65.8-million in its domestic debut, according to studio estimates released Sunday (final numbers come Monday).

Chris Evans plays Captain America. (Courtesy Paramount Pictures and Marvel Entertainment)

That Marvel troika has collectively grossed nearly $400-million domestically, and “Thor” and “X-Men” have grossed an additional $450-million-plus globally, according to BoxOfficeMojo.com — all but guaranteeing that Marvel will gross more than a billion dollars this summer from the power trifecta.

Avengers assemble, indeed.

Foreign box-office receipts were not yet available Sunday for “Captain America,” which in some countries — apparently to hedge against any anti-Yankee sentiment — was being billed simply as “The First Avenger.”

(Speaking of that title: As Captain America/Steve Rogers, star Chris Evans is one of very few Americans currently fronting an American superhero franchise-to-be. While foreign-born actors now wear the costumes for Batman, Superman, Spider-Man, Thor and Green Lantern, for instance, there was speculation that Hollywood didn’t want to test its luck by casting a non-American as Captain America.)

With Cap’s strong launch, Marvel’s successful season now positions the studio well for next summer’s scheduled release of “The Avengers.”

“Captain America’s” cinematic shield also was able to deflect and topple the record-setting phenomenon that is the final “Harry Potter” in the series. “Deathly Hallows — Part 2” grossed $48-million domestically its second weekend out, and has grossed a whopping $834-million already globally.

“First Avenger” benefited from largely positive reviews: The film received a cumulative critics’ index of “73” on RottenTomates.com and a score of “67” on Metacritic.

“In any other [non-superhero-glutted] cinematic era, ‘Captain America: The First Avenger’ would be a bona fide movie event, the kind of swiftly moving, eye-popping, effects-heavy spectacle for which movies were made. ... ,” writes Post film critic Ann Hornaday, who also notes:

“ ‘Captain America’ might hold the most promise, not just of saving the world, but of saving comic book movies from themselves.”

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