Ivan Lendl was the coach credited with a dramatic turnaround in the fortunes of Scots tennis superstar Andy Murray.
The partnership produced last year's Wimbledon title, the 2012 US Open and an Olympic gold medal.
But the pair have now parted company after two years.
In a joint statement, it appeared Czech-born Lendl, an eight-time Grand Slam champion, may have been the instigator of the split.
"Working with Andy over the last two years has been a fantastic experience for me", said the 54-year-old, who is rated one of the world's all-time great players.
"He is a first class guy. Having helped him achieve his goal of winning major titles, I feel it is time for me to concentrate on some of my own projects moving forward, including playing more events around the world, which I am really enjoying."
Murray, who is now ranked as the world's sixth best tennis player, teamed up with US-based Lendl in December 2011 with the aim of bringing the "experience and knowledge that few others have, particularly in major tournaments".
The Scots star, who has been making a tennis tour comeback after back surgery six months ago, added yesterday: "I am eternally grateful to Ivan for all his hard work over the past two years, the most successful of my career so far.
"I will take some time with the team to consider the next steps and how we progress from here."
There were no signs of the split last week when, after a recent dip in form, Murray insisted things would be no different if Lendl had been with him more during training.
That came just before he was knocked out of the BNP Paribas Open in Indian Wells in the fourth round to the world No 12 Milos Raonic, from Canada.
Murray admitted it was "not good enough", citing one of the reasons as a lack of confidence.
Twelve days previously, after being beaten in the semi-finals of the Acapulco Open by the world's 19th ranked player, Grigor Dimitrov, he sent a message on social networking site Twitter to calm fears about his performances.
He replied to a subsequent message from one fan expressing how he was "very concerned" over his form, saying: "Don't be ... I'm very close to being back to my best."
Before yesterday's announcement, Lendl, who had not travelled to the last tournament, was expected to reunite with Murray next week for the first time since January's Australian Open when the Scot defends his Miami Masters Series title.
Murray had previously worked with the likes of Leon Smith, Mark Petchey, Brad Gilbert, Miles Maclagan and Alex Corretja.
The player had been runner-up in four Grand Slam finals. Only one other man in the Open era, which began in 1968, lost his first four major titles finals, and that was Lendl.
Murray's majors breakthrough came in 2012 when he defeated defending champion Novak Djokovic in the US Open final at Flushing Meadows to win his first Grand Slam singles title.
He then ended a 77-year wait for a British men's singles champion at Wimbledon last summer with a memorable victory against the same player.
Lendl has recently played exhibitions in Kansas City, Oklahoma City, Nashville, Charlotte and London and given coaching clinics, as well as opening new courts in Bluffton, South Carolina, at the Ivan Lendl Junior Tennis Academy.
The coach added: "I will always be in Andy's corner and wish him nothing but great success as he, too, goes into a new phase of his career."
Why are you making commenting on The Herald only available to subscribers?
It should have been a safe space for informed debate, somewhere for readers to discuss issues around the biggest stories of the day, but all too often the below the line comments on most websites have become bogged down by off-topic discussions and abuse.
heraldscotland.com is tackling this problem by allowing only subscribers to comment.
We are doing this to improve the experience for our loyal readers and we believe it will reduce the ability of trolls and troublemakers, who occasionally find their way onto our site, to abuse our journalists and readers. We also hope it will help the comments section fulfil its promise as a part of Scotland's conversation with itself.
We are lucky at The Herald. We are read by an informed, educated readership who can add their knowledge and insights to our stories.
That is invaluable.
We are making the subscriber-only change to support our valued readers, who tell us they don't want the site cluttered up with irrelevant comments, untruths and abuse.
In the past, the journalist’s job was to collect and distribute information to the audience. Technology means that readers can shape a discussion. We look forward to hearing from you on heraldscotland.com
Comments & Moderation
Readers’ comments: You are personally liable for the content of any comments you upload to this website, so please act responsibly. We do not pre-moderate or monitor readers’ comments appearing on our websites, but we do post-moderate in response to complaints we receive or otherwise when a potential problem comes to our attention. You can make a complaint by using the ‘report this post’ link . We may then apply our discretion under the user terms to amend or delete comments.
Post moderation is undertaken full-time 9am-6pm on weekdays, and on a part-time basis outwith those hours.
Read the rules hereComments are closed on this article