By Agence France-Presse
The movie, the 11th installment in the X-Men series based on characters from Marvel Comics, netted $174.9 million abroad, the biggest foreign debut ever for an R-rated title.
The movie features Ryan Reynolds playing the foul-mouthed and irreverent title character as he forms an X-Force team to protect a young mutant from the evil Cable (Josh Brolin).
For an uber-bad guy, Brolin is having a very good week. He also plays world-destroying villain Thanos in Marvel's "Avengers: Infinity War," which led North American ticket sales before "Deadpool" bumped it off.
"Avengers" -- the fourth highest-grossing film in history, starring Robert Downey Jr., Benedict Cumberbatch, Scarlett Johansson and Chris Hemsworth -- took $29.5 million, pushing its global take past $1.8 billion.
Third in theaters was Paramount's new rom-com "Book Club," at $13.6 million. The film stars Jane Fonda, Diane Keaton, Candice Bergen and Mary Steenburgen as aging friends who decide to read the steamy "Fifty Shades of Grey" and find it expanding their literary and personal horizons.
In fourth was "Life of the Party," a Warner Bros. comedy, at $7.6 million. Melissa McCarthy, who co-wrote the script with her husband, director Ben Falcone, plays a newly divorced mother who returns to the college she dropped out of, where her daughter now studies.
And in fifth was Universal thriller "Breaking In," at $6.8 million. Online reviews collator Rotten Tomatoes, summing up the critical reaction, described the film as a "disposable action thriller."
But critics praised Gabrielle Union's performance as a mother trying to protect her children from hostage-takers.
Rounding out the top 10 were:
"Show Dogs" ($6 million)
"Overboard" ($4.6 million)
"A Quiet Place" ($3.9 million)
"Rampage" ($1.6 million)
"I Feel Pretty" ($1.3 million)