PITTSBURGH -- Grant Jackson, the top left-hander out of the bullpen for the 1979 World Series-champion Pirates, passed away Tuesday. He was 78.

Jackson’s former Pirates "Fam-a-lee" teammate Omar Moreno, who shared six seasons with Jackson in black and gold, was the first to share the news through Twitter. The Pirates said Jackson's death was due to COVID-19 complications.

“This pandemic has affected every family throughout our community, and the Pirates family is no different," Pirates president Travis Williams said. "As the winning pitcher for the Pirates in Game 7 of the 1979 World Series, Grant was a World Series champion and All-Star, who remained dedicated to the Pirates and the city of Pittsburgh since his retirement in 1982. He was an active board member of our Alumni Association who was always willing to help make an impact in our community. More so than any on-field accomplishment, Grant was a proud family man. Our sincere condolences and support go to his wife Millie [Milagro], his children Debra, Yolanda and Grant Jr., as well as his 10 grandchildren. He will be missed.”

Jackson enjoyed a long career as a Major League pitcher, appearing in 692 games over his 18-year career after debuting at age 22 with the Phillies in 1965. He spent time with six teams, most notably the Phillies, Orioles and Pirates -- all of whom he spent parts of six seasons with, respectively.

The 1970s were among the most successful decades in Pirates history, and Jackson helped make sure the fruitful period ended on a winning note. The southpaw, who was born and raised one state over in Fostoria, Ohio, was dealt to Pittsburgh by the Mariners, who had selected him from the Yankees in the 1976 Expansion Draft, then flipped him a month later.

After reaching the World Series with the Orioles in 1971 and the Yankees in ‘76, Jackson was back in the Fall Classic in ‘79 with the Pirates, who won the National League East title after rattling off 98 wins. Facing his former Baltimore club in the World Series, Jackson pitched like a man on a mission despite his first three scoreless appearances coming in losses.

Manager Chuck Tanner gave Jackson the ball in the fifth inning of Game 7 with Pittsburgh down by one run and two Orioles on base. He escaped by inducing a pop fly, then the Bucs' bats backed him with two runs in the sixth.

With his hot hand, Jackson continued to pitch into the eighth inning, when he walked two batters before giving way to closer Kent Tekulve to finish out the title clincher. Jackson, who earned the win in Game 7, was the only Pirates hurler to make an appearance in the 1979 World Series who did not allow a run.

By the time Jackson's contract was purchased from the Pirates by the Expos in 1981 at age 38, he had pitched in 278 games (353 1/3 innings) with Pittsburgh, recording a 3.28 ERA with 36 saves, including a career-high 14 in '79.

In his career, Jackson pitched 1,358 2/3 innings with a 3.46 ERA with 79 saves.