Heinz Günthardt, Martina Hingis’s Swiss Fed Cup captain, said he believed she was capable of playing on tour until she was 50 years old.

She made it to 37, and though two previous Hingis retirements turned out to be sabbaticals, this one seems like the real deal. “You want to stop on top and not when you’re already going backward,” she said in Singapore before playing her final match, a loss in the semifinals of the doubles tournament at the WTA Finals on Saturday.

At the time of her first two retirements, Hingis was nowhere near any sort of tennis pinnacle. In 2003, when she stopped at 22, she was in chronic pain and had not won a Grand Slam singles title in more than four years.

After coming back to the tour in 2006 and rising to No. 6 in singles, her momentum faltered and she ended up retiring again in November 2007, at 27, after deciding not to contest a positive test for trace amounts of cocaine. She was later suspended for two years.