Hall of Fame tennis coach Nick Bollettieri died Sunday night at his home in Florida after a series of health issues. He was 91.

He instructed at least 10 players who held a No. 1 world ranking, including Andre Agassi, Boris Becker, Jim Courier, Monica Seles, Maria Sharapova, Martina Hingis and Serena and Venus Williams.

“When he became sick, he got so many wonderful messages from former students and players and coaches,” his manager Steve Shulla told the Associated Press on Monday. “Many came to visit him. He got videos from others. It was wonderful. He touched so many lives and he had a great send-off.”

Bollettieri remained involved in coaching into his 80s. In 2014, he became only the fourth coach inducted into the International Tennis Hall of Fame.

“I forged my own path, which others found to be unorthodox and downright crazy,” he said during his induction speech at the hall in Newport, R.I. “Yes, I am crazy. But it takes crazy people to do things that other people say cannot be done.”

He opened the Bollettieri Tennis Academy in Bradenton, Fla., in 1978, which was purchased by IMG in 1987.

–Field Level Media