PARIS, France -- Legendary tennis coach Nick Bollettieri, who helped develop superstars such as Andre Agassi and Maria Sharapova, has died aged 91, the IMG Academy announced in a statement on Monday.

"Nick Bollettieri, the legendary tennis coach and founder of Nick Bollettieri Tennis Academy, which served as the foundation for today's IMG Academy, has passed away," read the statement.

While his methods were sometimes controversial, his academy in Florida churned out top players and he was to coach 10 players who would go on to become number one in the world.

Monica Seles, Jim Courier, Anna Kournikova and Mary Pierce were other stars who passed through his Bradenton complex.

Bollettieri also advised Venus and Serena Williams and Boris Becker.

"Tennis wouldn't be where it is today without Nick's influence," said Jimmy Arias, IMG Academy director of tennis and one of Bollettieri's original students.

"His tennis academy, which I had the privilege of growing up within, not only served as a launching pad for many tennis greats but evolved into an institution that has had a profound impact on the development of athletes across many sports at all levels."

Bollettieri founded the Nick Bollettieri Tennis Academy -– now IMG Academy –- in 1978 with a focus on intense physical training, total immersion, and ongoing competition among the most talented players in the world.

His enthusiasm for coaching continued almost right up to the end.

"Even in his last days, you could often find him on campus, coaching and mentoring young student-athletes and staff with the same passion and enthusiasm as he did in his 20s," said Tim Pernetti, President of IMG Academy Bradenton, a division of IMG Academy.

"Our heart goes out to his wife, Cindi, and his children. He has made a permanent and lasting impact on all of us."

Tommy Haas -- a four-time Grand Slam semi-finalist and world number two -- posted a moving tribute to the Korean War veteran.

"So many memories, I am not sure where to begin," posted the 44-year-old on Instagram.

"Nickiiii, 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."

© Agence France-Presse