The mould-breaking and hugely charismatic tennis coach Nick Bollettieri has died aged 91.

Bollettieri first established his eponymous academy in 1978, and before long students were living and training full-time in Bradenton, Florida.

With his deep tan and wrap-around sunglasses, Bollettieri worked his pupils extremely hard, and changed the face of tennis coaching.

"You were a dreamer and a doer, and a pioneer in our sport - truly one of a kind," former world number two Tommy Haas said in a tribute.

Sabine Lisicki - runner-up at Wimbledon in 2013 - said Bollettieri "shaped the game of tennis".

"You have given so many children a place to work for their dream," she added.

"Supporting them with your knowledge and the belief that anything is possible."

Bollettieri was never an elite player. He started offering tennis lessons shortly after his release from the US Army's 187th Airborne Division in 1957.

It was to his academy that Sharapova's father first turned, when his daughter arrived in the US aged six. Initially too young to board, the Russian later described it as a "tennis prison". The routine and repetition fashioned many champions, even if Sharapova felt there was not enough work on the technical aspects of the game.

Agassi used similar language in his autobiography, referring to his fellow students as "inmates." He was another who did not enjoy his tennis education. The American rebelled frequently against the system, and has recalled Bollettieri's anger after he played a final in jeans, makeup and earrings.

But the partnership endured. As a travelling coach, Bollettieri is most closely associated with Agassi, and the 1992 Wimbledon Championships. Agassi won his first Grand Slam on Centre Court, with Bollettieri wiping away tears in the players' box.

The Williams sisters, Jim Courier and Martina Hingis are among the other great champions to have benefitted from Bollettieri's experience, and current director of the IMG Academy - the modern iteration of Bollettieri's academy - Jimmy Arias said: "Tennis wouldn't be where it is today without Nick's influence."

He had an extraordinary presence. 'Holy mackerel!' was his catchphrase; tennis was his life.

Bollettieri was a natural on camera and we always looked forward to his appearances in the BBC Radio commentary box at Wimbledon in more recent years.

With a winning smile, and a wonderful turn of phrase, he brought the language and glamour of New York City to Centre Court.