Giuseppe di Stefano, who died yesterday in Milan at 86, was a lyric tenor whose sparkling voice was considered among the finest in 20th-century opera. A mainstay at the Metropolitan Opera during the 1950s, he was also Maria Callas’s favorite singing partner.

“Di Stefano sang like a god,” she once said. He toured with Callas on her final tour in 1973–74.

Di Stefano excelled at lighter fare, such as Rodolfo in Puccini’s “La Bohéme” and the Duke in Verdi’s “Rigoletto,” the role in which he made his Met debut in 1948.

The Met’s longtime general manager, Rudolf Bing, wrote in a memoir: “The most spectacular single moment [in 1949–1950] had come when I heard his diminuendo on the high C in ‘Salut! Demeure’ in Faust. I shall never as long as I live forget the beauty of that sound.”

But Bing was less impressed with di Stefano’s work habits, and in 1952 he fired di Stefano for missing rehearsals. Having pleaded illness for his absences, di Stefano was in reality back in Milan singing at La Scala. The two didn’t make up until the 1955–56 season, when di Stefano returned to sing featured roles in “Faust,” “Carmen,” and “Tosca.”

His voice began to deteriorate early; whether this was from abuse or something else remains contentious among opera lovers, but his career was, for the most part, over by the late 1960s. “His lack of discipline soon harmed what might have been a career men would remember with Caruso’s,” Bing lamented. Di Stefano acknowledged that he smoked heavily, stayed up late, and chased women. But he blamed his decline on an undetected allergy to synthetic fibers used in rugs.

Di Stefano was born July 24, 1921, in Sicily to a policeman and a seamstress. The family moved to Milan when he was young, but he had no musical training growing up. He became a seminarian and was discovered as a member of his local church choir. A wealthy benefactor paid for music lessons. His aspirations to the priesthood ended when he encountered a young seamstress his mother had sent to pick up goods at the family’s apartment. “I happened to be home from the seminary and … end of story,” he told Opera News in 2000.

During World War II, he was drafted, but a doctor who’d heard him sing gave him a medical dispensation. He supported himself by singing pop songs in theaters between feature films. He later fled to Switzerland, where he made his first opera recordings. He made his opera debut in 1946, and by 1947 he was singing at La Scala.

From the beginning, di Stefano’s singing was characterized by great emotion, and he was quick to claim that his feelings came from the heart. He recalled that he would practice the Italian singing tradition of abstinence before a performance, but he secretly kept his girlfriend at his hotel. This left him in a state of high tension.

“And when I went on stage — I was the Duke in Rigoletto — I couldn’t hold the high notes because it hurt so much,” he said in the Opera News interview. An ice pack placed in his leotard quenched the fires of love, but “by the second act, the ice melted and I was dripping.”

He began singing with Callas in 1951 in a performance of “La Traviata” in São Paolo. The two made 10 complete opera recordings together, including a 1953 version of “Tosca” considered a landmark by audiophiles. There were rumors of an affair.

By the early 1960s, critics were complaining that di Stefano could no longer sing true pianissimo. He took on heavier roles from this time on, perhaps exacerbating the damage. Luciano Pavarotti had his first big break in international opera when he covered for an ailing di Stefano as Rodolfo in “La Bohéme” at Covent Garden in London in 1963. Di Stefano’s later recordings are “painfully stentorian,” according to the International Dictionary of Opera.

After leaving the stage, di Stefano abandoned opera, refusing to give master classes.

“People who are born to sing will find their own way,” he told Opera News. “People who study all their lives are wasting their time.”

He spent half of each year at a seaside villa in Kenya, where he loved the climate despite having contracted malaria there. In 2004, thieves broke in and beat him, leaving him in a coma. He recovered somewhat, but remained an invalid and died, his wife said, from the lingering effects of the assault.