Brussels, May 6:

Former World No 1 Kim Clijsters of Belgium announced her immediate retirement from tennis on Sunday, cutting short plans to stop playing at the end of the season because of chronic injuries.

The fourth-ranked Belgian ended her 10-year career. In a statement on her Web site, Clijsters said: “It has been more than fun, but the rackets are being hung up. Stopping at almost 24 years of age is pretty young, but it’s been fun. It would have been nice to go on for several months. Money is important, but not the most important thing in my life. Health and private happiness are so much more important.”

The 23-year-old Clijsters lost 7-6 (3), 6-3 to Ukrainian qualifier Julia Vakulenko in the second round of the clay-court J&S Cup in Warsaw, Poland, in her final ever match on Thursday.

The 2005 US Open champion said her struggles with injury had taken its toll and that it was time to focus on other things, including her July 14 wedding to American basketball player Brian Lynch.

“It’s tiring to get out of bed and to use an hour just to warm up stiff muscles in the morning,” she said. The constant injuries and continual rehabilitation... it makes it all even more difficult to go on.”

A left wrist injury last year stopped Clijsters from defending her only Gland Slam title at Flushing Meadow and from playing in the Fed Cup final. She reached the 2007 Australian Open semi-finals, but injured her hip. Earlier this month, Clijsters had complained of back pain after losing in Key Biscayne.

Clijsters also won the 2002 and 2003 WTA Tour Championships as part of her 34 singles titles. She was Belgium’s first tennis player to reach No 1, holding the top-ranked spot for 19 weeks in 2003.