"Ocean's Thirteen," released by Time Warner unit Warner Bros. Pictures, is the third film to team Clooney and company with director Steven Soderbergh for a franchise inspired by the 1960 "rat pack" adventure starring Frank Sinatra, Dean Martin and Sammy Davis Jr.
And it is the latest in a flurry of big-studio sequels to arrive in theaters since the unofficial start of the summer movie season last month, following "Spider-Man 3," "Shrek the Third" and this week's No. 2 film, "Pirates of the Caribbean: At World's End."
"For a third installment, and there's been a lot of them this year, that tells you it's still a solid franchise," Paul Dergarabedian, president of box office tracking firm Media By Numbers, said of "Ocean's" performance.
By comparison, "Ocean's Eleven" and "Ocean's Twelve" grossed $38.1 million and $39.2 million during their respective first weekends in December 2001 and 2004, and they went on to amass more than $795 million worldwide together.
The top 12 films at the North American multiplex this weekend collectively grossed $133.6 million, down more than 9% from the same weekend last year when Disney's computer-animated racing film "Cars" opened with $60 million.
But overall domestic box office is up more than 10% year-to-year since May, a sign that the summer sequel formula is working for Hollywood.
Disney's third "Pirates" adventure, which had sailed atop the box
office for the past two weekends, sank to No. 2 in its third week with $21.3 million in U.S. and Canadian receipts, according to studio figures compiled by Media by Numbers.
Starring Johnny Depp, Orlando Bloom and Keira Knightley, "At World's End" has grossed a total of $253.6 million in domestic distribution so far.
The bawdy comedy "Knocked Up," from Universal Pictures, slipped a notch to No. 3 but held up relatively well in its second weekend with $20 million in ticket sales, a decline of 35 percent from its opening three-day tally.
Opening behind it at No. 4 was Hollywood's latest computer-animated penguin tale, "Surf's Up," from Sony Pictures Entertainment, grossing $18 million.
The animated storybook satire "Shrek the Third" grossed $15.7 million in its fourth weekend to round out the top five. The DreamWorks Animation SKG film, released through Viacom's Paramount Pictures, has now racked up nearly $282 million in domestic release.
Another of the summer's blockbuster sequels, "Spider-Man 3," fell from fifth place to No. 8 at the domestic box office with $4.4 million in its sixth weekend, bringing its North American tally to $325.7 million.
Its worldwide cumulative gross stands at $865 million, making it Sony's biggest global success.
This weekend's only other wide release, the Lionsgate horror film "Hostel: Part II," opened at No. 6 with $8.8 million in receipts.