Australian tennis coach Bob Brett died after a battle with cancer at the age of 67 on Tuesday morning.
Brett worked with grand slam champions Boris Becker, Goran Ivanisevic, Johan Kriek and Marin Cilic in his almost 50-year career.
The Melbourne-born man famously coached Becker to become the No.1 ranked tennis player in the world between November 1987 and February 1991.
Becker also won the 1989 Wimbledon and US Open under Brett's guidance.
Australian tennis coach Bob Brett , who coached Boris Becker to world No.1, has died after a long battle with cancer at the age of 67
He also coached Australian players Paul McNamee and Peter McNamara.
McNamee said Brett's passing left a 'big hole' in Australian tennis.
'He's one of the unsung heroes of Australian tennis, because of the impact he had around the world,' McNamee told the Herald Sun.
'He's one of our greatest-ever coaches and you'd have to put him up there with Mr Hopman, Tony Roche and Darren Cahill.
'He was a salt-of-the-earth Aussie. He always kept the accent, was a true blue guy and was never affected by his success - he was the same guy from beginning to end.'
Serena Williams' coach, Patrick Mouratoglou, also paid his tributes to Brett on Twitter.
'Extremely saddened by the passing of Bob Brett with whom I have collaborated during six years and who has taught me so much in my early years as a coach,' he wrote.
'One of the best coaches I have met. Rest In Peace.'
Brett coached a number of Grand Slam champions like Goran Ivanisevic, Johan Kriek and Marin Cilic in his almost 50-year career. He also coached Australian players Paul McNamee and Peter McNamara
Becker celebrates after winning the Men's Singles tournament at Wimbledon in 1989. 'I'm a very sensitive animal and he found the right words for me,' Becker said after his Wimbledon victory
Brett was born in Melbourne in 1953 and developed an interest in tennis from a young age, spectating various Championships in 1965.
He worked as a ball boy for the US Davis Cup team, where he observed top players like Arthur Ashe and Clark Graebner, in 1965 and for the Australian Davis Cup team the following year.
But he was unable to pursue his own professional tennis careers and worked as a postman and a second evening job from 1971 until 1974.
Brett then decided to pursue a career in coaching and learnt from Australian coach Harry Hopman at the Port Washington Tennis Academy from 1974.
By 1978, he began coaching his own players such as Andrés Gómez, Johan Kriek, Fritz Buehning, Tim Wilkison, and José Luis Clerc.
Later additions included Tim Mayotte, Mats Wilander, Guy Forget and Henrik Sundström.
In 1987, he began coaching Boris Becker and led him to win Wimbledon and the US Open in 1989.
'I'm a very sensitive animal and he found the right words for me,' Becker said after his Wimbledon victory.
Brett at the Australian Open in Melbourne in 2000. In his final years, Brett lived in Melbourne where became known for his charitable work such as with the Australian Prostate Cancer Foundation
From 2000, Brett worked alongside both former and current stars of Japanese men’s tennis.
Brett also established the Bob Brett School of Tennis in San Remo, Italy.
In 2014, Brett was assigned and served as the head of player development for the British Lawn Tennis Association before resigning in 2015.
In his final years, Brett lived in Melbourne where he became known for his charitable work such as with the Australian Prostate Cancer Foundation.
In 2020, he established a non-profit association in Australia, the Kent Yamazaki & Bob Brett Tennis Foundation, which supports disadvantaged youth in Australia.
He was also awarded the ATP Tim Gullikson Career Coach Award in November last year.
He is survived by his two daughters, Caroline and Katarina, and his brother, Arthur Brett, who is a four-time Olympic coach in sailing.
Brett when he coached for the Japan Davis Cup team in India. He was awarded the ATP Tim Gullikson Career Coach Award in November last year