Wimbledon champion Andy Murray has split with coach Ivan Lendl after two years, the British world number six said.
A statement on his Twitter page said they had mutually agreed to end a partnership that saw Murray win two grand slam titles and a gold medal at the 2012 London Olympics.
"I'm eternally grateful to Ivan for all his hard work over the past two years, the most successful of my career so far," said Murray, who became Britain's first Wimbledon men's singles champion for 77 years when he beat Novak Djokovic last year.
"As a team, we've learned a lot and it will definitely be of benefit in the future. I'll take some time with the team to consider the next steps and how we progress from here."
Since winning Wimbledon last year Murray's form has dipped, not helped by having back surgery towards the end of 2013. He is yet to win a title this year and was knocked out in the quarterfinals of the Australian Open by Roger Federer.
Eight-time Grand Slam champion Lendl, 54, said he wanted to concentrate on his own projects. "Working with Andy over the last two years has been a fantastic experience for me," Lendl said. "He is a first class guy. Having helped him achieve his goal of winning major titles, I feel like 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.
"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."
Until Murray teamed up with Lendl he had fallen short of winning a Grand Slam title.