Peter Graf, who as the coach and manager of the tennis great Steffi Graf acquired the nickname Papa Merciless for his stern control of almost every aspect of her life, died on Saturday in Mannheim, Germany. He was 75.

Steffi Graf announced the death on her website. News reports said the cause was pancreatic cancer.

Peter Graf’s career in tennis was tempestuous. He was accused of verbally abusing officials, manipulating his daughter’s schedule to preserve her ranking and coaching her illegally from the stands. He got into a fistfight with an American millionaire at the French Open. Most notably, he was accused of mismanaging the millions his daughter had won and at one point was said to be carrying around her winnings in paper bags.

In 1997, Graf was convicted of failing to pay $7.3 million in taxes on his daughter’s earnings and attempting to evade another $1.8 million through a tangled scheme of shell companies and tax havens. He served 25 months in prison. The judge exonerated Steffi Graf.

News reports suggested that the tax matter had alienated father and daughter, as had a very public brouhaha in 1990, when a German magazine accused Peter Graf of fathering a daughter with a Playboy model. Openly distressed after that scandal broke, Steffi Graf was eliminated from the three remaining Grand Slam tournaments after winning three the previous year.