Liev Schreiber starrer The Bleeder has its official out-of-competition screening here at the Venice Film Festival this evening, before stepping into the Toronto ring on September 10. Directed by Monsieur Lazhar Oscar nominee Philippe Falardeau, The Bleeder tells the real-life story of Chuck Wepner, the journeyman underdog boxer who was 35 when he improbably pushed world champ Muhammad Ali to the limit in their 1975 title fight. Schreiber also produces the redemption drama that’s not entirely a boxing pic, even if he took 800 real punches to ensure authenticity during filming.

Schreiber, who this evening receives the Persol Tribute to a Visionary Award, and Falardeau are on the Lido along with Naomi Watts, Schreiber’s real-life wife who plays Wepner’s partner Linda. She’s the one who steered him through troubles after the Ali fight — which included a prison stint for cocaine possession — and ultimately to sobriety and redemption. Elisabeth Moss, Jim Gaffigan and Pooch Hall also star. (Check out a clip here.)

Wepner is known as the inspiration for Sylvester Stallone’s iconic Rocky Balboa character. Schreiber said today that Stallone has been “incredibly generous to us, relating to me his stories about that time for him when he wrote Rocky and his relationship with Chuck. I owe him a big, big thank you. He has been a friend to the film.”

The passion project for Schreiber started when Watts got a call from an editor friend who wanted to get the script to him. “I was immediately a fan of it, not just because of my love of boxing but more because of getting to know the character of Chuck,” he told reporters. He noted that what moved him most about Wepner’s story was “the openness with which he went down the rabbit hole of narcissism. As an actor, that cautionary tale aspect of our passion to be loved and adored by many often complicates our ability to appreciate one. That part for me, ironically a boxing movie that was really mostly about love, was really exciting.”

Wepner, he added, has “an effortless ability to make mistakes and learn from them. You have to be willing to stumble and take risks and then you learn such a profound lesson about love.”

Watts said she opted for the role of Linda, which has less screen time than Moss’ Phyliss, because it “felt like a complete departure. I liked her spunk and level of wisdom. … I also feel that being a real-life couple and then playing a couple onscreen can be distracting sometimes.”

Schreiber chimed in: “Naomi also likes the high-wire act, and Linda couldn’t be further from her. The first time I saw her walk out of the trailer with the red lipstick and the fake boobs and the leopard tights, I knew it was going to be f*cking awesome.”

Reviews today have been very strong for The Bleeder, which Schreiber produced with Mike Tollin, Carl Hampe, Christa Campbell and Lati Grobman; Jeff Rice is exec producer. UTA and Nu Image are co-repping U.S. rights; Nu Image is selling internationally.