Nick Bollettieri, tennis coach who worked with Serena Williams, Venus Williams and Andre Agassi, dies at 91

Nick Bollettieri, a legendary tennis coach who worked with the Williams sisters, Andre Agassi and Boris Becker, has died. He was 91.

Bollettieri founded the Nick Bollettieri Tennis Academy in 1978. The company was purchased by IMG Academy a few years later. IMG confirmed Bollettieri's death, calling him "one of the best tennis coaches of all time" in a statement.

The academy also released a video in memory of Bollettieri.

Bollettieri worked with a number of elite tennis stars during his time as a coach. Serena Williams and Venus Williams worked with Bollettieri and spent some time at his academy. Agassi, Jim Courier and Monica Seles were among his successes as well. Bollettieri also worked with Maria Sharapova and Anna Kournikova, among others. In total, Bollettieri worked with 10 players who would go on to reach No. 1 status.

Tennis professionals and former students pay tribute to Nick Bollettieri

Some of Bollettieri's former students paid tribute to Bollettieri on social media. Agassi thanked Bollettieri in a post on Twitter.

Sabine Lisicki, who was the runner up at Wimbledon in 2013, said she will cherish the memories she made with Bollettieri.

Tommy Haas, who was the men's No. 2 ranked tennis player in May of 2002, called Bollettieri, "truly one of a kind."

Bollettieri was inducted into the Tennis Hall of Fame in 2014.