Ahead of the weekend, Warner Bros said it expected "Deathly Hallows: Part 1" to break the $100 million barrier in the United States and Canada, while some box office watchers speculated it could reach as high as $150 million.

But only two previous movies have broken into that range. Batman film "The Dark Knight" has the best-ever debut with $158 million in 2008, and No. 2 "Spider-Man 3" had a $151 million debut in 2007, according to Hollywood.com Box-Office.

Dan Fellman, head of domestic distribution for Warner Bros, told Reuters that "Deathly Hallows" performed well among all audiences and core fans had not wavered in their support.

"What sets this apart is that the audience has aged right along with the movie and the cast," Fellman said.

He declined to forecast a final domestic box office tally when the movie ends, but did say that he believed it would "start with a 3," meaning somewhere north of $300 million.

Of six previous "Potter" movies, only two have ended above that, "Harry Potter and the Sorcerer's Stone" ($317 million) and "Harry Potter & the Half Blood Prince" ($301 million).

Rounding out the top five films in the United States and Canada were comedy "Due Date," in the No. 4 spot with $9.1 million, and behind it was the debut of the Russell Crowe drama, "The Next Three Days," with $6.8 million.

Warner Bros, which also released "Due Date," is a unit of Time Warner Inc. "Megamind" was produced by DreamWorks Animation Inc and released by Paramount Pictures, a unit of Viacom Inc.

"Unstoppable was distributed by 20th Century Fox, a unit of News Corp, and "The Next Three Days" was distributed by the film division of Lions Gate Entertainment.