The box office underwent a religious conversion this weekend as Christian crowds flocked to War Room, lifting the low-budget salute to prayer above the Zac Efron drama We're You're Friends and the Owen Wilson thriller No Escape.

Filmed for a mere $3 million and distributed by Sony's Affirm division, War Room more than tripled its production budget in a single weekend, picking up $11 million from 1,135 locations. That also easily topped projections that had it debuting in the $4 million to $5 million range, although in retrospect those estimates were overly conservative given that advance ticket sales were unusually strong.

"These are the kind of outlier events that happen and wake everyone up to the fact that faith-based audiences are passionate and looking for content," said Paul Dergarabedian, senior media analyst at Rentrak.

The film is the latest faith-based hit from director Alex Kendrick and his brother, writing and producing partner Stephen Kendrick, the pair behind Fireproof and Courageous. It marks the biggest debut of their careers.

"There is so much love for this film," said Rory Bruer, Sony's distribution chief. "It starts with the Kendricks. They're visionaries in this genre."

Despite the success of War Room, Straight Outta Compton topped charts for a third consecutive weekend, becoming the first film to manage that feat since Jurassic World. The rap biopic about the early days of NWA. pulled in an impressive $13.2 million, pushing its domestic total to $134.1 million. It is now the highest-grossing musical biopic, trumping the Johnny Cash drama Walk the Line and its $119.5 million domestic haul.

War Room reaffirms the potency of faith-based crowds, ranking along previous hits such as God's Not Dead and Heaven is for Real, but aside from its success, there was very little to celebrate.

The month of August sputtered to a close as the trio of new releases failed to inject much life into ticket sales. The overall box office was down more than 20 per cent from the year-ago period when Guardians of the Galaxy was still drawing big crowds. That comparison is problematic, however, given that Labor Day fell during that period and the holiday has been pushed back a week this year.

No Escape, a thriller about an American family ensnared in a violent political coup in a nameless Asian country, finished in fourth place with $8.2 million from 3,355 locations. It has earned $10.2 million since debuting on Wednesday. The Weinstein Company paid just under $5 million for rights to the film, which was criticised in by some critics for being retrograde in its depiction of a developing country's culture and politics.

"We'll make money on it," said Erik Lomis, the Weinstein Company's distribution chief. "We're not big spenders on the [promotion and advertising] side and we spent late and did a good job getting to our target audience."

Not even the presence of Efron could lift We Are Your Friends at the multiplexes. The look at the electronic music scene bombed, eking out a paltry $1.8 million from 2,333 screens, making it the worst wide-release launch of the High School Musical star's career and one of the lowest wide-release debuts for a major studio film in history. Given that dreary pedigree, it's no surprise that We Are Your Friends fell far short of projections, which had it debuting to roughly $8 million. Warner Bros. spent $2 million to acquire it out of the American Film Market, limiting the studio's financial exposure.

"We're disappointed," said Jeff Goldstein, Warner Bros. distribution executive vice president. "We believe in Zac and this was a passion project of his."

The top five was rounded out by Mission: Impossible – Rogue Nation, which captured third place with $8.3 million, and Sinister 2, which nabbed fifth position with a $4.7 million finish. The latest Mission: Impossible has earned $170.4 million since debuting in July, while the second Sinister film has racked up $18.5 million in two weeks.