Former world number one Roger Federer has split with coach Paul Annacone after three and a half years.
The Swiss has slipped to seventh in the world - his lowest ranking for over a decade - and saw his hopes of reaching next month's end-of-season ATP World Tour Finals in London dented on Thursday by his third-round exit from the Shanghai Masters at the hands of Gael Monfils.
"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," the 32-year-old said in a statement on www.rogerfederer.com.
"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."
Federer joined forces with Annacone, the former coach of 14-time major singles winner Pete Sampras, in summer 2010, and has since won 13 titles.
However, the 17-time grand slam singles champion has claimed only one trophy this season and felt the time was right for himself and Annacone to go their separate ways.
"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," Federer added.
"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."