Roger Mayweather, trainer to nephew and champion boxer Floyd Mayweather, has died at 58 after a long battle with diabetes, his camp said on Tuesday.

Before becoming a legendary cornerman, the Grand Rapids, Michigan native was a champion in his own right.

He had a celebrated 20-year career, becoming a two-division world champion with notable fights against Julio Cesar Chavez and Pernell Whitaker.

• READ: Durant among 4 Nets to test positive for new coronavirus

"The Black Mamba" held the WBA and lineal super featherweight titles in the mid-1980s and the WBC light welterweight title later that same decade.

He held the IBO light welterweight title and IBO welterweight titles in the mid-1990s and finished with a 59-13 professional record.

He first began working with Floyd in the late 1990s and over 12 years helped shape him into one of the best pound-for-pound boxers of all time, amassing an unblemished 50-0 record.

"My uncle was one of the most important people in my life inside and outside of the ring," Floyd Mayweather said in a statement.

"Roger was a great champion and one of the best trainers in boxing. Unfortunately, his health was failing him for several years and now he can finally rest in peace.

"Roger meant the world to me, my father Floyd Sr., my uncle Jeff, our whole family, everyone in and around the Mayweather Boxing Gym and the entire boxing world. It is a terrible loss for all of us."

The loss of Roger is the second major blow to Floyd this month.

Last week his ex-girlfriend and the mother of three of his children, Josie Harris, was found dead inside a car in her driveway in Valencia, California.

Floyd responded by posting a series of photos of the couple on Instagram as a tribute to her.

(Reporting by Rory Carroll in Los Angeles; Editing by Ken Ferris and Toby Davis)

(For more sports coverage, visit the ABS-CBN Sports website).