"This Is It" represented 61 percent of sales for online ticket seller Fandango.com, according to Fandango representative Harry Medved.
Distributor Sony said Wednesday matinees for "This Is It" already had surpassed the film's haul from those first evening screenings. The studio paid $60 million for worldwide rights to the film, which was distilled from more than 100 hours of footage shot as Jackson rehearsed for what would have been a 50-concert comeback run in London starting last July.
While "This Is It" is not quite a concert film, box-office watchers are gauging its success against "Hannah Montana & Miley Cyrus: Best of Both Worlds Concert," the biggest concert movie on record. "Best of Both Worlds" had a $31.1 million opening weekend last year and pulled in $65.3 million domestically during its entire run.
"This Is It" so far has not approached any major box-office records. The best results ever for advance evening screenings came from "Pirates of the Caribbean: At World's End," which took in $13.2 million Thursday night ahead of its official Friday release in summer 2006. "Independence Day" had the best Tuesday night advance results, with $11.1 million in summer 1996.
Still, "This Is It" already is well on its way to becoming a top-grossing music documentary.
Last March's "Jonas Brothers: The 3D Concert Experience" runs a distant second to "Best of Both Worlds in the concert-film record books, topping out at $19.2 million. "Madonna: Truth or Dare" follows with $15 million, and last year's "U2 3D" is fourth with $10.2 million.
"As a genre, concert movies and even documentaries aren't usually the type of films to bring in big box-office bucks, but because of his name and also the timing of it, I think it's a winner," said Paul Dergarabedian, box-office analyst for Hollywood.com. "That $60 million investment I think was worthwhile."
Sony, which opened "This Is It" simultaneously in 99 countries, plans to release worldwide box-office results Thursday for the film's first full day.
"This Is It" faces some hurdles over its first weekend, which falls on Halloween, when the main competition will be scary movies such as "Paranormal Activity" and "Saw VI."
Halloween day itself, which falls on Saturday, typically cuts into theater business, with many fans skipping movies in favor of parties.
With Jackson's death just weeks before the concerts were to open, the rehearsal footage now stands as a final curtain call, and fans have been happy to get one last glimpse of the singer at work.
Some came away surprised at how precise and hands-on the soft-spoken Jackson was as he developed the musical numbers with his backup dancers and musicians.
"He was very, very much into every detail of his work," said Marilyn Morrison, who saw "This Is It" in New York City. "I always thought that he was so quiet and shy, but he was very authoritative, very detail-orientated."