In a normal summer, a debut like the estimated $29.0 million opening for Dwayne Johnson's "Hercules" would be reason for its creators and distributor to rejoice. After all, the movie did better than pundits had predicted (in the low 20s), and it enjoyed a healthy per-screen average ($8,067 per venue). As an action star with a track record, Johnson would be said to have delivered on his promise, and there would be backslapping and cigars all around for a $100-million PG-13 movie that would surely earn back its investment from both domestic and overseas audiences (who bought an estimated $28.0 million worth of tickets) .

And yet, that opening was good enough only for second place. Coming out more than 50 percent ahead to debut in the No. 1 slot was "Lucy," a French-made R-rated action movie starring petite Scarlett Johansson, shot for a modest (by action standards) $40 million. Playing on 422 fewer screens than "Hercules," "Lucy" nonetheless opened with an estimated $44.0 million (well above the low-30s range of predictions) and a very strong $13,875 per-screen average.

Both movies did very well -- anomalous enough, both because the movies would have been expected to cannibalize each other's audience, and because sales have been generally lackluster this summer. Yet "Lucy" came out so far ahead that the Rock has to be scratching his head and wondering why he didn't smell what Scarlett was cooking.

How did this decisive upset happen? Here are a few reasons:

Johansson is arguably a bigger star than The Rock. Perhaps she's coasting on residual good will from playing Black Widow in two of the biggest movies of recent years, "The Avengers" and "Captain America: The Winter Soldier." (For what it's worth, she also earned strong reviews as a deadly alien in this summer's little-seen indie sci-fi/horror flick "Under the Skin." So audiences were apparently ready to see her headline a glossy action blockbuster on her own.

Johnson does better with existing franchises. His most popular recent films have been the ones where he stepped into an existing successful franchise, like "G.I. Joe" or "Fast and Furious." On his own, in original stories, not so much. (Though you could argue that "Hercules," as a take on a familiar Greek mythological character, is part of the oldest franchise in the book.) Johnson does have a huge fan base (some 37 million people "like" him on Facebook), but he can't always persuade them to buy tickets (indeed, it looks like only about one in 10 of his Facebook following paid to see "Hercules").

Luc Besson knows his way around kick-ass babes. The French writer/producer/director has been making movies about slender-yet-strong heroines for 25 years, including such memorable creations as Nikita ("La femme Nikita,") Matilda ("The Professional"), Leeloo ("The Fifth Element") and Cataleya Restrepo ("Colombiana"). Even his biopics are about fierce women ("The Messenger: The Story of Joan of Arc," "The Lady"). So it makes sense that he'd succeed with "Lucy," about a woman who gains superpowers when she accidentally ingests an experimental drug.

Morgan Freeman has a Midas touch. Not that anyone went to see "Lucy" just because Freeman was in it, playing a scientist. But his august presence always lends movies (even ridiculous action vehicles like this one, or "Wanted") a certain gravitas and an implicit quality-control seal.

Brett Ratner has a reverse Midas touch. For many moviegoers, Ratner's hamfistedness put the kibosh on the Hannibal Lecter franchise (with"Red Dragon") and the X-Men franchise (with "X-Men: The Last Stand"). He took a surefire premise with an all-star comic cast ("Tower Heist") and couldn't even make a hit out of that. He's a competent visual storyteller, competent enough to make a movie where Dwayne Johnson plays Hercules, at any rate, but he always seems like he's trying too hard. Maybe the intended "Hercules" audience could smell the flop sweat.

It's all about women. This has been the summer of women at the box office, with hits like "Maleficent," "The Fault in Our Stars," and "Tammy," while movies aimed more squarely at guys ("The Amazing Spider-Man 2," "A Million Ways to Die in the West") have underperformed. The Rock is a handsome man, but he doesn't bring in the ladies. Johansson, on the other hand, seems to appeal equally to women and men, judging by the evenly-split audience for "Lucy."

Interestingly, quality seems not to have been a factor, even though "Lucy" played to an older (25-plus) audience that usually pays attention to reviews. In fact, it earned a dismal C+ grade at CinemaScore, indicating poor word-of-mouth. "Hercules" didn't get great reviews either, but it earned a much better B+ at CinemaScore.

Not that word-of-mouth may matter much either. Both movies are likely to get flattened this coming weekend when Marvel's "Guardians of the Galaxy" opens. But for now, Black Widow gets bragging rights over The Rock.

CATEGORIES Movies, Box Office