Rahman, who was one year younger than his iconic brother, made his professional debut in 1964, four years after Ali.
Fighting as a heavyweight, he amassed a record of 14–3 with one draw and hung up the gloves in 1972 after defeat to Jack O’Halloran.
By that time, big brother Muhammad – who had changed his name from Cassius Clay – was already the biggest star in the sport.
Ali was a former heavyweight champion on the comeback trail after losing three years of his career by refusing to serve in the Vietnam war.
And he enlisted the help of Rahman – who travelled everywhere with his brother as gofer after giving up boxing himself.
In an exclusive interview with SunSport, Ali’s younger brother said: “He’s the most famous man on the planet and I’m his brother.
“I was so close to him. I fought professionally too. I fought 20 professional fights. I won 16 fights. I lost three and one draw. I had amateur fights too.
“I was a very good boxer myself, but I helped my brother so I cut my career to help my brother and had one of hell of a time.
“My boxing career was very good.”