Reliance runs multiple TV channels and JioCinema streaming app through its media unit Viacom18 and has a sizeable hold over India's $28-billion media and entertainment market
Featuring a cast of misfit superheroes that includes a machinegun-toting raccoon, "Guardians" leapt from the pages of Marvel Comics to total $295 million in ticket sales in US and Canadian theatres, according to studio estimates.
"Teenage Mutant Ninja Turtles" was second with $6.5 million in ticket sales for the three days from Friday through Sunday on a relatively slow post-holiday weekend.
"If I Stay" was third with sales of $5.8 million, according to the box office tracking site Rentrak.
"Guardians of the Galaxy" was distributed by Walt Disney.
Viacom's Paramount Pictures released "Teenage Mutant Ninja Turtles."
"If I Stay" was distributed by Time Warner's Warner Brothers studio.