Martina Navratilova has ended her role as a part-time consultant to the world number nine Agnieszka Radwanska after just five months in the job.
The 18-time grand slam singles champion linked up with Radwanska in December with the aim of helping the Pole make an impact in the latter stages of more big tournaments.
But Navratilova said she had under-estimated the time she needed to devote to the 2012 Wimbledon finalist.
"I am stepping down as Agnieszka's part-time coach," Navratilova, 58, said in a statement.
"I think I under-estimated the time it would take to make this a proper and good situation for both Agnieszka and me.
"I really enjoyed working with Aga and her whole team and I wish her all the best for the rest of the season."
Radwanska, who is still searching for her first grand slam title, was beaten in the first round of the Stuttgart Grand Prix this week by Italy's Sara Errani.
"I just wanted to thank Martina for her time and effort over these last few months," Radwanska, 26, said on her Twitter account.
"It was a great experience to work with one of the all-time greats. However, we both agreed that as Martina could not commit 100 per cent to the project then it was not going to work as a long time partnership.
"We will stay friends and I wish her all the best in her personal and professional life."
Source: PA
