Bradenton, Florida - Renowned tennis coach Nick Bollettieri has died at the age of 91.

The charismatic American pioneered the concept of a live-in academy and guided some of the biggest names in the sport, including Andre Agassi, Maria Sharapova, Monica Seles, and Boris Becker.

Born in New York to Italian immigrant parents, Bollettieri switched to tennis coaching after dropping out of law school and opened his tennis academy in Bradenton, Florida, in 1978.

Sports management giant IMG bought the academy nine years later, but Bollettieri continued to oversee its tennis program.

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The Williams sisters were among other players who benefited from the larger-than-life Bollettieri’s help, while many academies have followed his blueprint.

Former world number two Tommy Haas, another Bollettieri success story and current tournament director of the BNP Paribas Open in Indian Wells, wrote on Instagram: "So many memories, I am not sure where to begin."

"Nickiiiii, that’s how I have called you for the longest time. Thank you for your time, knowledge, commitment, expertise, the willingness to share your skill, your personal interest in mentoring me, and giving me the best opportunity to follow my dreams."

"You were a dreamer and a doer, and a pioneer in our sport, truly one of a kind."