New York Mets legend Jerry Koosman died Sunday at age 83, the team announced.

Koosman was the winning pitcher in Game 5 of the 1969 World Series, which gave the franchise its first World Series title. That year's squad was dubbed both the "Amazin'" and "Miracle" Mets.

Longtime team employee Jay Horwitz said on social media Koosman had been battling "multiple illnesses."

The Mets, whose first season was in 1962, had never been above .500 after just nine games in any of their first seven years in existence. But the Amazin's showed promise early and ran away with the National League East in August.

On Aug. 13 that year, the Mets were 10.0 games behind the Chicago Cubs in the NL East, but in less than a month, they took over first place and wound up running away with the division en route to the title (with the help of the infamous black cat).

Koosman pitched to a 2.28 ERA that season, second on the team only to Cy Young Award winner Tom Seaver.

The left-hander spent 12 of his 19 seasons in Queens before spending time with the Minnesota Twins, Chicago White Sox, and Philadelphia Phillies. In New York, he had a 3.09 ERA. He also finished in second place in the 1979 NL Cy Young Award vote, losing to Randy Jones.

His number 36 was retired by the Mets in 2021, becoming the third player in franchise history to have his number retired after Seaver and Mike Piazza. Six others have since followed.