By Jonathan Overend
Roger Federer has unexpectedly split from coach Tony Roche just two weeks before the start of the French Open.
Federer is on his worst run of form since becoming world number one
The decision is described as "mutual" but follows Federer's surprise loss to Filippo Volandri at the Rome Masters.
Roche, the veteran former adviser to Ivan Lendl and Pat Rafter, began work with Federer two and a half years ago.
Federer said: "I thank Tony very much for his efforts and am grateful for the sacrifice he made travelling so far from his home in Australia."
After his breakthrough season in 2003, when he won his first Grand Slam title at Wimbledon, Federer sacked his previous coach Peter Lundgren.
An immediate replacement is not expected and Federer is likely to begin his French Open tilt alone.
The Roland Garros title remains the only Grand Slam to elude him.
When Federer played without a coach, in 2004, he won three Grand Slam titles.
Federer won six of his 10 Grand Slam titles alongside Roche and maintained his number one world ranking.