Martina Hingis faces Switzerland 's Agnieszka Radwanksa in the Fed Cup . Saturday 's tie will be her first singles match since 2007 . Hingis won all five of her Grand Slam titles by the age of 18 . The now-34-year-old retired at the age of 22 in February 2003 citing injuries .
Martina Hingis faces Poland 's Agnieszka Radwanksa in the Fed Cup . Saturday 's tie will be her first singles match since 2007 . Hingis won all five of her Grand Slam titles by the age of 18 . The now-34-year-old retired at the age of 22 in February 2003 citing injuries .