Christopher Nolan’s “Oppenheimer” has already received a handful of strong first reactions, but now comes a huge claim from “Taxi Driver” writer and “The Card Counter” director Paul Schrader. The Oscar nominee attended the New York premiere of Nolan’s atom bomb epic and took to social media afterwards to hail it as “the best, most important film of this century.”

“If you see one film in cinemas this year it should be ‘Oppenheimer,’” Schrader added in a Facebook post shared widely across social media. “I’m not a Nolan groupie but this one blows the door off the hinges.”

“Oppenheimer,” based on the 2005 book “American Prometheus” by Kai Bird and Martin J. Sherwin, tracks the creation of the atomic bomb during World War II through the eyes of theoretical physicist and Manhattan Project leader J. Robert Oppenheimer. Cillian Murphy stars in the lead role. The film also features Matt Damon as Manhattan Project director Gen. Leslie Groves Jr. and Robert Downey Jr. as Lewis Strauss, a founding commissioner of the U.S. Atomic Energy Commission. Emily Blunt, Florence Pugh and Benny Safdie also star.

Bird previously raved about Nolan’s “Oppenheimer” adaptation during a conversation at the Institute for Advanced Study last month.

“I am, at the moment, stunned and emotionally recovering from having seen it,” Bird said. “I think it is going to be a stunning artistic achievement, and I have hopes it will actually stimulate a national, even global conversation about the issues that Oppenheimer was desperate to speak out about — about how to live in the atomic age, how to live with the bomb and about McCarthyism — what it means to be a patriot, and what is the role for a scientist in a society drenched with technology and science, to speak out about public issues.”

“Oppenheimer” opens in theaters nationwide July 21 from Universal Pictures.