Tennis couple Martina Hingis and Radek Stepanek have called off their nine month engagement. The Swiss player, 26, and Czech tennis ace, 28, announced their plans to marry last January (07) after becoming engaged the month before (Dec06). A spokesman for the Association of Tennis Professionals says, "Radek asked me to pass on a message announcing that he and Martina Hingis have split up, they will remain good friends, and that is all I have to say." Former world number one Hingis has won five Grand Slam titles including one Wimbledon, three Australian and a U.S Open.But after a number of injuries she retired from the game at the age of 22.But in 2005 she returned to professional tennis after a string of successful operations. Since then she has climbed banck up the rankiings to number six.