Martina Hingis is returning to professional tennis in 2006

The 25-year-old Swiss, who retired from the WTA Tour three years ago because of an ankle injury, is hoping to return to the women's tennis circuit in early 2006 and resume a career which produced five Grand Slam singles titles and made her the youngest player to be ranked No. 1.

Hingis made a brief comeback in February, losing in the first round of the Volvo Women's Open in Thailand. Her previous match was at Filderstadt in October 2002, but she believed she prematurely returned to competition following left ankle surgery, and withdrew from all remaining tournaments.

Hingis won 40 singles titles and 36 doubles titles on the WTA Tour. She was only 16 1/2 when she took over the top ranking in March 1997. She spent 209 of the next 247 weeks in the top spot. She also is one of only five women to be ranked No. 1 in singles and doubles at the same time.

Hingis made her debut on the WTA Tour on Oct. 4, 1994, four days after her 14th birthday. In 1997, she won three of the four majors and missed the Grand Slam by losing the French Open final to Iva Majoli. In 1998, Hingis won all four doubles titles at the majors.

Hingis won US$18.3 million (Ђ15.52 million) in prize money, third in career earnings behind Steffi Graf and namesake Martina Navratilova, AP reports.

A. A.