By Sandy CohenLOS ANGELES -- Turns out zombies and Superman are no match for monsters. Disney's ( DIS) Monsters University is the weekend box-office winner, according to studio estimates released Sunday. The animated family film, which reunites stars Billy Crystal and John Goodman and their characters from the 2001 hit Monsters, Inc., debuted in first place with $82 million, beating out swarming zombies in World War Z and Superman himself in Man of Steel. "The diversity of this weekend is part of what makes this business so great," said Dave Hollis, Disney's head of distribution. "It's a really extraordinary weekend for the industry." Especially for Monsters University, Pixar's 14th consecutive film to open in first place. Such expectations of excellence put a "healthy pressure" on filmmakers, Hollis said: "To deliver that kind of quality consistently is a differentiator in the marketplace." Still, the film exceeded studio expectations with its domestic totals, he said. World War Z, Paramount's ( VIA) Brad Pitt zombie romp, overcame critical advance publicity to open in second place with $66 million. Media reports months ahead of the film's opening chronicled its problems, including a revamped ending that delayed its release. "What World War Z proves is that all the negative backstory that can be thrown at a movie doesn't matter if the movie's good," said Paul Dergarabedian of box-office tracker Hollywood.com. "I don't think the audience cares one lick if they had to reshoot the ending if they like the ending and like the movie." The success of the film means it could be a franchise in the making. "It's the biggest live-action original opening since Avatar," said Don Harris, Paramount's president of domestic distribution. It's "Brad Pitt's biggest opening ever, and in terms of Paramount's recent history, it ranks behind Iron Man and Transformers as the third largest potential franchise opening in the history of the company." Warner Bros. ( TWX) Man of Steel was third at the box office, adding an additional $41.2 million to its coffers and bringing its domestic ticket sales over $210 million in just the second week of release. The Sony ( SNE) comedy This Is the End, which stars Seth Rogen, James Franco and Jonah Hill as versions of themselves trapped in a mansion during the apocalypse, finished in fourth place.