Roger Federer has unexpectedly parted ways with coach Tony Roche two weeks before the start of the French Open.
"I thank Tony very much for his efforts over these last years, during which I appreciated the 12-15 weeks per season we would work together," the world number one said in a statement released on his web site (www.rogerfederer.com) on Saturday.
"I am also grateful for the sacrifice he made, travelling so far from his home in Australia and leaving his family."
The decision follows Federer's poor run of form in recent weeks. For the first time since becoming world number one in February 2004, the Swiss has gone four tournaments without capturing a title.
Federer has worked with the 61-year-old Australian, who had previously coached Ivan Lendl and Pat Rafter, on a part-time basis since 2005.
During their partnership Federer won six of his 10 Grand Slam crowns and maintained his place on top of the world rankings.
The 25-year-old is now expected to turn up at Roland Garros without an adviser but that is unlikely to cause him much concern.
After winning his first Grand Slam at Wimbledon in 2003 under Peter Lundgren's guidance, Federer sacked the Swede less than six months later.
He then went on to lift three more majors in 2004 when he opted to go it alone.
The French Open is the only Grand Slam Federer has yet to win.
Federer needs to win the Roland Garros title to become only the third man after American Don Budge and Australian Rod Laver to hold all four majors at the same time.