MGM's tennis-based romance "Challengers" opened this weekend atop the North American box office, taking in an estimated $15 million behind positive reviews and the powerful net game of actor/singer Zendaya, industry watcher Exhibitor Relations reported Sunday.

"This is a strong opening for a romance and sports drama," said analyst David A. Gross, crediting Zendaya's star power and the directorial talents of Luca Guadagnino (he of "Call Me By Your Name").

"This is the right material with the right director, featuring the right star at the right time," Gross said.

Zendaya plays a tennis prodigy who retires after an injury, then later helps her husband (Mike Faist) prepare for a key match against a player (Josh O'Connor) who, awkwardly enough, is both her former lover and his onetime best friend.

By the way, yes, Zendaya can play tennis. She trained for three months with tennis pro Brad Gilbert, and Guadagnino told Variety that she was so good he rarely had to use film of her double.

In second spot for the Friday-through-Sunday period was another new release, Lionsgate and Kingdom Story Company's faith-based drama "Unsung Hero," at $7.8 million.

The partly fact-based film follows a man who moves his music-loving family from Australia to the United States after his concert promotion business collapses. Friendly fellow churchgoers and the power of prayer (spoiler alert) just might help him and his seven kids turn things around.

In third, for the second straight weekend, was Warner Bros.' "Godzilla x Kong: The New Empire," at $7.2 million. The humongous gorilla and giant reptile, not natural buddies, team up this time to save their species -- and ours.

Meantime, A24's "Civil War," a disturbing saga about a dystopian America in the near future, dropped three places from last weekend's top spot, earning $7 million.

Kirsten Dunst plays a veteran photojournalist who finds herself increasingly tormented as she travels through a blood-soaked country in hopes of interviewing a besieged third-term president.

And in fifth, down two spots, was Universal's horror film "Abigail" at $5.3 million. Alisha Weir plays 12-year-old Abigail, whose kidnappers learn too late that she is a killer vampire.

Rounding out the top 10 were:

"The Ministry of Ungentlemanly Warfare" ($3.9 million)

"Kung Fu Panda 4" ($3.6 million)

"Ghostbusters: Frozen Empire" ($3.3 million)

"Dune: Part Two" ($1.9 million)

"Boy Kills World" ($1.7 million)