Tennis star

Kim Clijsters

announced yesterday she is retiring at 23.

The former U.S. Open champion, from Belgium, once ranked No. 1, initially planned to quit after the season. Now, with injuries having exacted too much and her thoughts turning to family and a "new life," her retirement is immediate.

"Health and private happiness are so much more important," she said on her Web site.

Still ranked No. 4, Clijsters said she was wary of the injuries that have led to fatigue, lack of motivation and a decline in play.

"It's tiring to get out of bed and to use an hour just to warm up stiff muscles in the morning," she wrote in Dutch on her online diary. "The constant injuries and continual rehabilitation . . . it makes it all even more difficult to go on."

Clijsters made the decision after losing in straight sets to Ukrainian qualifier Julia Vakulenko in her final match Thursday, failing to defend her title in Warsaw, Poland.

Clijsters has been playing for 10 years and won 34 career singles titles, including the 2002 and 2003 WTA Championships. She had wanted to go out with style, making Wimbledon the last Grand Slam tournament of her career. Instead, her summer will be marked by her July 14 wedding to Brian Lynch, a former Villanova basketball player now playing in Belgium.

In other tennis news:

* Philipp Kohlschreiber won his first title by beating doubles partner Mikhail Youzhny, 2-6, 6-3, 6-4, at the BMW Open in Munich, Germany.

Colleges

* Tennessee's Monica Abbott became the NCAA's career softball strikeout leader, overtaking Olympian and former Texas star Cat Osterman. Abbott tied Osterman last weekend at 2,265 strikeouts. She then struck out six yesterday against Alabama, putting the record - covering all NCAA divisions - at 2,271. Osterman was at the game as an ESPN commentator.

* Officials in Omaha, Neb., are considering plans for a new baseball park that would replace Rosenblatt Stadium, the home of the College World Series. Rosen-blatt has been home to the series since 1950. In addition to the College World Series, Rosenblatt is home to the Omaha Royals minor league baseball team.

Sport Stops

* Panathinaikos won its fourth Euroleague basketball title by beating defending champion CSKA Moscow, 93-91, in Athens, Greece.

* An unidentified runner collapsed at the finish line of the Flying Pig Marathon in Cincinnati and later died, race organizers said.

Philly File

* Nick Luukko, of West Chester, was the final player selected in the Ontario Hockey League priority draft. Luukko, 15, a freshman at Malvern Prep, was a 15th-round selection by the London Knights. A defenseman, he plays for Team Comcast, an AAA traveling youth hockey team from Pennsauken, N.J. Luukko will attend camp with the Knights in June, and intends to return home for school in the fall. He is the son of Comcast-Spectacor president Peter Luukko.

* In men's lacrosse, Saint Joseph's lost to Providence, 9-4, in the title game of the Metro Atlantic Athletic Conference championships in Emmitsburg, Md. With a win, the Hawks (6-12) would have earned an automatic bid to the NCAA Tournament. *