Martina Navratilova's brief stint as coach of 2012 Wimbledon runner-up Agnieszka Radwanska is finished.

Navratilova, who won 18 Grand Slam singles titles as a player, and Poland's Radwanska, who is currently ranked No. 9, issued statements Friday to announce the parting.

They announced in December that they would work together.

Radwanska is only 13-11 this season, including a first-round loss Wednesday in a clay-court tournament at Stuttgart, Germany.

A statement posted to Radwanska's Twitter account thanks Navratilova "for her time and efforts over these last few months" and calls it a "great experience to work with one of the all time greats."

The post adds that the women "agreed that as Martina could not commit 100 (percent) to the project then it was not going to work as a long term partnership."

The French Open starts May 24.