"Guardians of the Galaxy" ultimately became the fifth highest grossing movie in Marvel's series of 14 interconnected films.
"There was a huge question mark next to the title of this movie for a lot of people, analysts and critics included. And then once again Marvel worked their magic," said Paul Dergarabedian, senior media analyst at comScore.
Now, the franchise has the wind at its back. The star of leading man Chris Pratt has risen appreciably in the last three years, and fans are buzzing about the return of the rag-tag group that includes Star-Lord, Gamora, Rocket Racoon, Groot and Drax.
The movie drummed up the most new conversations in comScore's latest analysis on social media chatter. The total volume of talk has surged about 33 percent during the past five weeks.
"'Guardians' has marked another pillar of pre-release buzz for Marvel. Hype through social media channels has been strong for months on end, and the trailers have generated overwhelmingly positive reactions," said Shawn Robbins, analyst at BoxOffice.com.
However, the sequel was not necessarily bulletproof. A big part of the allure of a sleeper hit like "Guardians of the Galaxy" is that it comes out of left field, Dergarabedian told CNBC prior to the U.S. debut.
"It's hard to capture lightning in a bottle twice, and it was that whole newness of it, the unknown quantity that played into the charm of it," he said.
Still, glowing reviews played a role in the first film's success, he noted. "Guardians of the Galaxy Vol. 2" has an 82 percent "Fresh" rating on Rotten Tomatoes, trailing the original by nine percentage points.
That score slipped six percentage points over the last week as more reviews poured in, with some critics lamenting the sequel is not quite as fresh as the original. But it remains Marvel's seventh best rated movie.
"Guardians" also stands to benefit from a relatively uncrowded release date, arriving three weeks after "Fate of the Furious" and two weeks before "Alien: Covenant" debuts, Dergarabedian said. It gets a chance to pull in holdouts during the Memorial Day holiday, he added.
"Guardians of the Galaxy Vol. 2" has one more trend on its side: With the exception of "The Avengers" franchise, Marvel's second movies have outperformed the originals at the box office.