Roger Federer has split with tennis coach Paul Annacone after more than three years working together.
Federer made the announcement just two days after crashing out in the third round of the Shanghai Masters to Gael Monfils.
The former world number, now seven in the rankings, revealed on his website that he was calling time on his relationship with Annacone, who also coached Pete Sampras during his glory years.
Federer said: "After a terrific three and a half years working together, Paul and I have decided to move on to the next chapter in our professional lives.
"When we started together we had a vision of a three-year plan to win another Grand Slam title and get back to the number one ranking.
"Along with many other goals and great memories, these two main goals were achieved.
"After numerous conversations culminating at the end of our most recent training block, we felt like this was the best time and path for both of us.
"Paul remains a dear friend, and we both look forward to continuing our friendship. I want to thank Paul for his help and the value he has added to me and my team."
Annacone started working with Federer in August, 2010, and the American took the Swiss star to a seventh Wimbledon title in 2012, his most recent major title.