Jake LaMotta, the iron-chinned brawler whose exploits in and out of the ring during boxing's heyday served as the basis for the Oscar-winning Raging Bull, has died at 95.

LaMotta's longtime fiancée, Denise Baker, said he died Tuesday at a Miami-area hospital from complications of pneumonia. He was believed to be the oldest living former boxing champion.

Perhaps no other man embodied the stature of boxing during a time it reigned as one of North America's most popular sports.

The Bronx-bred fighter with an aggressive style provided the visceral thrills that made boxing so popular. He was the only man in Sugar Ray Robinson's first 132 bouts to defeat the fighter often considered the greatest, pound for pound, who ever lived.

While middleweight champion, LaMotta saved his title in a fight he was losing with a desperate 15th-round stoppage over Quebec-based Laurent Dauthuille.

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LaMotta, left, and Sugar Ray Robinson Jr. pose for photographers at Madison Square Garden in New York on April 7, 2006, in a ceremony commemorating boxing great Sugar Ray Robinson Sr. (Teddy Blackburn/Reuters)

LaMotta was also a poster boy for the brutality of boxing, through his extreme capacity to absorb punishment, never getting knocked down in his prime. Most notably, LaMotta was pounded relentlessly by Robinson in a Feb. 14, 1951, bout that became known as the St. Valentine's Day Massacre.

''If the fight had gone another 20 seconds, Sugar Ray would have collapsed from hitting me so much," LaMotta quipped decades later about the 14th-round stoppage. The media, however,deemed it a "blood-letting fight."

Confirmed underworld influence on boxing

Worse yet, LaMotta was a party to, and helped blow the lid off, a barely held secret — underworld control of boxing. Appearing at a U.S. Senate subcommittee hearing years after his career ended, he admitted that, in exchange for a promised title shot, he took a dive in a 1947 bout against Billy Fox, who he said "couldn't dent a bowl of yogurt."

At those hearings called by U.S. Senator Estes Kefauver in 1960, LaMotta admitted he lied when he told the New York district attorney days after the Fox bout that it was on the up and up. He testified to receiving $100,000 US, minus a $20,000 payment given to French champion Marcel Cerdan's handlers.

The statute of limitations for criminal prosecution had ended, but the retired pugilist was asked if he feared reprisals of a different kind, at street level.

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LaMotta, right, against Frenchman Marcel Cerdan on June 17, 1949, the bout that landed him the world middleweight title. (AFP/Getty Images)

"I'm not afraid for myself," LaMotta said, while tearing up strips of paper. "And I'm not afraid of those rats!"

He apologized at another juncture: "I thought I was right then. I just wanted to be champion."

LaMotta had already reached his nadir by then. After his retirement from boxing, he owned and managed bars and tried his hand at acting. An underaged girl was found to be taking on paying clients in a Miami club he ran, leading to a six-month prison sentence for abetting prostitution in 1958.

Inspiration for De Niro, Scorsese

LaMotta wrote about all of it in 1970's Raging Bull: My Story, a book that captured the imagination of Robert De Niro. The actor on the rise for his Mean Streets and Godfather II work persuaded friend Martin Scorsese to direct the project.

Following LaMotta's death, De Niro issued a statement saying, "Rest in Peace, Champ."

Raging Bull was released in November 1980 and hailed for its nostalgic but gritty black-and-white look, compelling antihero and brutal fight scenes that strayed from the often-cartoonish mayhem of boxing movies.

The film focuses on LaMotta's tumultuous relationships with manager/brother Joey and second wife, Vikki, played to praise by relative unknowns Joe Pesci and Cathy Moriarty. De Niro, meanwhile, famously packed on over 50 pounds to depict LaMotta in middle age. 

Longtime New York Times film critic Vincent Canby called it Scorsese's "most ambitious film as well as his finest."

"Raging Bull is the most painful and heartrending portrait of jealousy in the cinema, an Othello for our times," said Roger Ebert. "It's the best film I've seen about the low self-esteem, sexual inadequacy and fear that lead some men to abuse women."

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Robert DeNiro, Cathy Moriarty, LaMotta and Martin Scorsese, left to right, pose for photographers at a 25th-anniversary screening of Raging Bull, on Jan. 27, 2005. (Chip East/Reuters)

'They captured the real me'

New York Times sportswriter Red Smith called it a film about "a creep, a highly unappetizing specimen of the human race." Smith posited it was only made because of the Oscar-winning success of Rocky in 1976, and to give De Niro a chance to flex his Method Acting muscles.

LaMotta agreed with Smith's assessment about his character, but not the film's accuracy and quality.

"I can't be mad at Bobby De Niro and Marty Scorsese," he told the Washington Post. "I was a sick animal. They captured the real me."

The film performed modestly at the box office but was nominated for eight Academy Awards, with De Niro winning for best actor and Thelma Schoonmaker earning best editor honours. 

Raging Bull lost out on best picture to Ordinary People, but its estimation would rise through the years. The American Film Institute ranked Raging Bull behind only Citizen Kane, The Godfather and Casablanca on its 2007 all-time list. The AFI also deemed it the top sports movie of all time, despite boxing scenes that only comprise about 10 minutes of the two-hour running time.

Inaugural boxing Hall of Famer

Born Giacobbe LaMotta on July 10, 1921, his was a hardscrabble upbringing in a Bronx tenement. During the Depression, he engaged in petty crime as a teen before finding his way to a gym.

Following a brief amateur career, he fought 19 times in his first eight months as a professional in 1941. He would go on to win three of four bouts against former champ Fritzie Zivic and beat Tony Janiro in a fight in which he said he turned down a fix offer from gangsters.

LaMotta was 26 when he beat Cerdan for the middleweight title in June 1949 with a 10th-round stoppage. They were set for a rematch later in the year, but the Frenchman was killed in a plane crash.

LaMotta battled Robinson six times in all, winning only once, but never hitting the canvas against the man who knocked out dozens.

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LaMotta at a Sept. 15, 2015, baseball game between the Tampa Bay Rays and the New York Yankees. (Will Vragovic/The Tampa Bay Times via AP)

The pair, along with Muhammad Ali and others, were inducted in the inaugural class of the International Boxing Hall of Fame in Canastota, N.Y., in 1990, a posthumous honour for Robinson.

LaMotta was married seven times; his last was in 2013. He had four daughters and two sons.

His son Joseph was on the Swiss Air plane that crashed into the Atlantic Ocean near Peggy's Cove, N.S., killing all 229 aboard in 1998. Another son, Jake Jr., died earlier that year of cancer.

Vikki LaMotta, mother to those sons and daughter Christi, wrote her own autobiography on the heels of Raging Bull, and posed for Playboy at age 51. She died in 2005 at age 75.

Unlike many men who took far fewer blows, LaMotta was lucid enough in old age to take part in an off-Broadway show about his life. A New York Times profile at the time described a 90-year-old puffing on a Marlboro at his kitchen table between reminiscences.

With files from The Associated Press