“Rise of the Planet of the Apes” swung to the number one spot this weekend as it opened to an estimated $54 million in sales at the North American box office. A prequel to the 1968 film “Planet of the Apes,” it tells the story of how experiments gone awry lead to an epic battle between man and his ancestral species. The film's receipts were “much better than expected,” said industry analyst Paul Degerabedian. The 20th Century Fox action thriller “Rise of the Planet of the Apes” took in $54 million to open as the No. 1 movie, according to studio estimates Sunday. That was about $15 million to $20 million more than analysts expected for the “Apes” prequel, though well below the $68.5 million opening of Tim Burton's “Planet of the Apes” remake 10 years ago. Featuring James Franco, Freida Pinto and Andy Serkis, “Rise of the Planet of the Apes” tells the story of how lower primates began evolving to take over Earth from humans. Though small and blue, “The Smurfs” proved resilient at their second week at the box office while reaping $21 million in second place, industry tracker Exhibitor Relations estimated. The hybrid live-action and animated film, starring Neal Patrick Harris and featuring the voice of pop star Katy Perry, has so far generated nearly $129 million in worldwide sales. After entering at number one last week, Hollywood action thriller “Cowboys & Aliens” marked its second week at theaters with a projected $15 million in sales, slipping to third spot. Comedy date flick “The Change-Up” marked its debut weekend in fourth place with $13.5 million in sales, as “Captain America: The First Avenger” showed some muscle, slipping just two spots to fifth place with $13 million. Summer blockbuster “Harry Potter and the Deathly Hallows — Part 2” dropped from fourth to sixth place during its fourth week at theaters. The eighth and final installment of the Potter series has already broken multiple records at the box office, including single-day sales ($92.1 million) and midnight premier sales ($43.5 million) on its way to surpassing $1 billion in worldwide sales.