Martina Hingis has announced her retirement from tennis for a third time.
The 37-year-old Swiss revealed the news at the WTA Finals in Singapore, where she is playing in the doubles event with partner Chan Yung-jan.
Quoted on srf.ch, Hingis said: "It's the right time for me. It's better to stop at the peak and I can say I had a very good time.
"The successes I've had over the past three years have been great and it's going to be hard to beat anyway. And my priorities change, too, of course."
Hingis returned to the sport for the third time in 2013 and forged a hugely successful career in doubles, winning 10 more grand slam titles, taking her overall tally to 25.
"My priorities change, too, of course."
She retires ranked as the doubles world number one and as the holder of the US Open women's doubles title and mixed titles at Wimbledon and in New York.
Hingis prompted speculation about her future at the US Open when she stopped short of committing to going for a third straight mixed crown with Britain's Jamie Murray at the Australian Open.
Hingis was a child prodigy and the youngest ever grand slam champion, winning the women's doubles with Helena Sukova at Wimbledon in 1996 at the age of just 15.
The following year she dominated in singles, winning the Australian Open, Wimbledon and US Open titles and reaching the French Open final.
She was ranked world number one aged 16 and added two more grand slam singles titles in her teens as well as completing the women's doubles Grand Slam in 1998.
But Hingis began to struggle with ankle problems and announced her retirement from tennis in 2003 aged just 22.
Four years later Hingis returned with more success, winning two WTA Tour singles events in 2006 and qualifying for the WTA Finals as well as winning her first mixed doubles grand slam title.
But injuries began to take their toll once more and then in November 2007 Hingis announced she had tested positive for a metabolite of cocaine at Wimbledon.
She appealed but was given a two-year ban by the International Tennis Federation and retired again, but was back in 2010 playing in the seniors doubles events at several grand slams and competing in World Team Tennis.
After being inducted into the International Tennis Hall of Fame in the summer of 2013, Hingis announced she was making another comeback on the main tour, this time only in doubles.
As a player lacking the power of many of her modern rivals but with sublime touch and a sharp tennis brain, it was no surprise to see Hingis flourish.
She won just her second slam title in 13 years with Sania Mirza in the women's doubles at Wimbledon in 2015 and then added the mixed title with Leander Paes the following day.
Hingis and Mirza won 41 straight matches, racking up titles at the US Open, WTA Finals and Australian Open, but fell short of a non-calendar Grand Slam when they were beaten in the third round of the French Open.
Hingis' subsequent achievements also included a first Olympic medal when she and Timea Bacsinszky claimed silver in the women's doubles in Rio last summer.