"Lucy," starring Scarlett Johansson as a woman with a super-powered brain, collected $44 million to win at domestic box offices, outmuscling "Hercules," but both releases helped pump life into a lackluster summer at U.S. and Canadian theaters.

"Hercules," starring Dwayne "The Rock" Johnson in the title role, took in $29 million for second place, while "Dawn of the Planet of the Apes," which topped the box office the past two weekends, finished third with $16.4 million.

"Lucy" stars Johansson as a traffic-stopping, object-moving woman whose brain operates at abnormally high levels after a drug is planted in her body. The special effects-laden film was made for a relatively inexpensive $40 million, according to Box Office Mojo.

Made for a brawny $100 million, "Hercules" got mixed reviews from critics, according to site Rotten Tomatoes, with 50 of 80 reviewers giving it a "fresh" rating.

Both films exceeded opening weekend industry expectations.