Boris Becker has ended his role as coach of Novak Djokovic, just months after the Serb joined the elite group of players who have won all four Grand Slams.
During their three years together, Djokovic saw his game reach new heights as he kicked the habit of frequently losing Grand Slam finals and enjoyed 122 weeks as World number one.
Having won every Grand Slam bar the French Open last year, he took the Australian Open this year with a stunning straight-sets win over Andy Murray and beat the Scot again at Roland Garros to claim his elusive first French Open and 12th Grand Slam in all.
However, since then Djokovic has seen his form drop off and a resurgent Murray has snatched away the world number one ranking. Now, Becker has said, Djokovic needs to "go back to the office" and practice more.
Fans booking corporate hospitality for the Championships, Wimbledon next summer may be fascinated to see who Djokovic employs next as he tries to recapture his best form.
Discussing the ending of the partnership, Djokovic said: "The goals we set when we started working together have been completely fulfilled," while Becker said: "If somebody would have told us three years ago we are going to win six Grand Slams together, regain the number one spot in the world and just be the most dominant player, I would have signed up for that."
However, he went on to describe the last few months as "challenging", due to Djokovic having a few injuries and struggling to stay focused as he sought to spend more time with his family off-court.
The German added: "He didn't spend as much time on the practice court in the last six months as he should have and he knows that."
Such words confirm what some suspected in the latter months of 2016; that having completed the set of Grand Slams, Djokovic lost some focus as he had achieved everything he had set out to do. A series of injury niggles did not help either, and he may have only reached the US Open final thanks to a succession of injury withdrawals by opponents, saving him for a final that he lost to Stan Wawrinka.
However, given a good break to regain fitness, a new coach and the target of trying to recover the world number one spot, Djokovic may be back with a vengeance in 2017.
Murray could certainly face a new and different challenge in the new year as world number one, with Becker warning him it is tough at the top.
Speaking to the Mail on Sunday last week in an interview that hinted his partnership with Djokovic might be ending, Becker said Murray will "ride the wave" in his first few months, but will "start to feel it in May", as it is from then on that he has a lot of points to defend in almost every tournament.
Becker also predicted that the biggest challengers to Murray and Djokovic in 2017 will not be the ageing Roger Federer or Rafael Nadal, but up-and-coming youngsters like Dominic Thiem, Nick Kyrgios and Milos Raonic.
He also described Britain's Kyle Edmund as a player possessing "a great attitude who can go a long way".