London - Former world number one Ana Ivanovic has parted ways with Steffi Graf's former coach Heinz Gunthardt after enduring a topsy-turvy season.
The 2008 French Open champion's ranking plummeted to 65th in July this year after hooking up with Gunthardt in February but appeared to turn a corner when she ended a two-year title drought by capturing the Linz Open trophy last month.
While that run of form helped her to climb back to 24th in the world, the Serbian felt she needed a coach who could give her undivided attention.
Gunthardt, who helped Germany's Graf to win 12 of her 22 grand slam titles in the 1990s, combined his role as coach with that of a television commentator.
"I'm very grateful to Heinz for all his hard work, and for sharing his knowledge with me," Ivanovic said in a statement. "We had nice success together and we definitely made improvements to my game.
"Looking ahead, I really need a full-time coach who is with me at all tournaments and during training periods. Heinz has family and other obligations, which I fully respect, so he is unable to give me the kind of commitment I am looking for."
Gunthardt added: "It's been a real pleasure working with Ana. She's got lots of talent and I feel in the last few months the hard work that we have put in started to pay off. If Ana feels she needs a coach at her side full-time to be able to further improve, it cannot be me.
"I wish her all the best and I will be supporting her."