And before It came along, Paramount's Paranormal Activity 3 boasted the biggest opening for a horror film with $52.6 million.

It continues an enviable winning streak for New Line, which Emmerich ran for many years before getting the top gig at Warners last year. (The Conjuring series is another recent New Line victory, including current box-office champ Annabelle: Creation.)

New Line has long been a bastion for horror, but It takes it to a new level, playing like a four-quadrant tentpole and jolting the domestic box office back to life after a tough summer that saw attendance hit a 25-year low and revenue plummet by 15 percent.

"It's humbling when something performs beyond your wildest expectations. Speaking for my colleagues at Warner Bros. and New Line, we are incredibly happy and relieved. All the hard work paid off, but but we know there was a certain amount of luck involved. I like to think New Line is really good at nurturing filmmakers and Warners is really good at marketing," Emmerich told THR on Sunday. "I think in general, the box office is more and more a world of the have and have-nots."

When New Line was folded into Warner Bros. in 2008, both sides agreed that New Line should focus once again on horror. It, which had been in development at Warners, was subsequently ceded to New Line. Director Cary Fukunaga left the project over creative differences, with New Line hiring Argentine filmmaker Andres Muschietti (Mama) to replace him, according to insiders.

"It has now taken horror into the $100 million openers club and raises the bar for the money making potential of the genre," says comScore analyst Paul Dergarabedian. "Not to mention that once they hit the small screen, they are equally as appealing."

It follows a group of misfit kids in the 1980s who battle the demonic Pennywise the Dancing Clown, played by Bill Skarsgard. The pic follows the success of the Netflix original series Stranger Things, which likewise is set in the 1980s and revolves around a group of kids banding together to battle a supernatural threat.

"That's the message of the movie — that if we stick together and friendship is true and real, we can defeat evil," says Emmerich.

"There is something about this movie that people are ravenously interested in. It isn't just about Stephen King, it isn't just about clowns and it isn't just about the 1980s, although the '80s are a thing and has a certain panache. We as a studio are betting big on the 1980s, including Steven Spielberg's Ready Player One," Emmerich continued.

It also redefines how Hollywood views the month of September, which has never seen a movie open to such heights. Previously, Hotel Transylvania 2 was the crown holder with a $48.6 million debut.

Adds Jeff Goldstein, president of domestic distribution for Warners: "It is just what the industry needed."