Hall of Famer Martina Hingis, one of only six women's players to hold the No. 1 ranking in both singles and doubles at the same time, will retire after the WTA Finals, she announced Thusday.
"Looking back now, it's hard to believe that almost exactly 23 years ago I made my professional debut," Hingis wrote in a Facebook post. "The years that followed have been some of the most rewarding years of my life, both personally and professionally, but I believe the time has come for me to retire, which I will be doing after my last match here in Singapore."
Hingis, 37, won Grand Slam titles Nos. 24 and 25 at the US Open in September, capturing the women's doubles and mixed doubles titles. Overall, she won 13 major doubles titles, along with five in singles and seven in mixed doubles.
She held the world No. 1 ranking for 209 weeks during her career, winning 43 WTA singles titles and 64 doubles titles. The Swiss star still is the youngest Grand Slam champion in history, having won the Wimbledon doubles title when she was just 15.
"I feel very lucky to have been given the opportunity to play this wonderful sport for so many years," Hingis said. "Tennis has always been my passion and I am extremely thankful for all the challenges, opportunities, partnerships and friendship it's given me."
Hingis was inducted into the International Tennis Hall of Fame in 2013. She also has won an Olympic silver medal and had a 29-7 overall record in Fed Cup matches during her career.
"Martina is a true champion and a great ambassador for the sport of women's tennis," WTA CEO Steve Simon said in a statement. "She has contributed greatly to the entire sport, both in her home country of Switzerland and across the globe. She will certainly be missed on our tour. ... She will be remembered as one of the greatest players to have played the game."
Hingis first walked away from tennis in 2003 because of injuries.
She returned to the sport in 2006, but left the game again after testing positive for cocaine during the 2007 Wimbledon tournament. Despite having already retired, in 2008 she was sentenced to a two-year ban from tennis for the positive drug test.
"The previous times (I retired), I always had things in the back of my head that I might be able to, singles and then doubles, might be able to do that," Hingis said. "I think now it's definite. Before I was thinking I might come back."
In 2013, Hingis returned to tennis as a doubles-only player. She won 10 of her Grand Slam doubles titles since coming out of retirement in 2013.
Hingis said while she is stepping away from the competitive side of the sport, she is looking forward to new challenges.
"This isn't a goodbye," Hingis said. "As history shows, I haven't been able to stay away from tennis for long in the past."
The Associated Press contributed to this report.