Done again? Another twist in the bizarre career of Martina Hingis

Is she a proud athlete or is this another twist in the topsy-turvy career of Martina Hingis? It's a harsh but legitimate question now that she has decided to retire for a third time.

On Thursday at a news conference in Singapore, Hingis unexpectedly announced she was walking away from the game again. The timing of the decision came in much the same way she traveled through the game for 23 remarkably successful and often bizarre years.

Earlier in the day, she and partner Yung-Jan Chan had advanced to the final four of the WTA Finals, their 19th straight win. (Hingis will finish this event before hanging it up.)

In September, Hingis won Grand Slam Nos. 24 and 25, in doubles and mixed, at the US Open. So why now? She and Chan are the No. 1 team in the world, after all.

"I think it's perfect timing," Hingis said Thursday. "You know, you want to stop on top and not when you're already going backwards."

Give Hingis this: She knows what it looks like at the top, and she knows what it is to go backwards. The careers of most players are roughly bell shaped. Hingis' looks like a page torn from a seismograph during a day of unusual volcanic activity.

This is a player who was mature enough at the age of 16 in 1997 to fall one singles match short of a calendar-year Grand Slam. Less than two years later, she was also one haughty enough to throw a tantrum, break down in tears and nearly get herself booed off the court at the French Open because of her unsportsmanlike conduct in a match with much-loved Steffi Graf.

At the time, she had already played in eight Grand Slam singles finals, winning five. She wouldn't win another.

Yet Hingis remained competitive and held the No. 1 ranking, off and on, for 209 weeks until as late as 2001. She was quick, with plenty of touch, soft hands and a great tactical sense. But she was just 5-foot-7 and neither explosive nor muscular. The game began passing her by as the Williams era dawned.

Hingis retired from tennis for the first time following her second ankle surgery, in May of 2003. She said she wanted to concentrate on her equestrian interests and to complete her education. But her real genius was for tennis, and she couldn't stay away long. She played sparingly in 2005 and mounted a full-blown singles comeback in 2006, where still just 26, she finished the year ranked No. 7.

While injuries became an inhibiting factor the following season, Hingis was ultimately forced out of the game in November 2007 after she tested positive at Wimbledon for a metabolite of cocaine. She ended up suspended until October 2009.

Afterward, Hingis remained at the fringes of the game, then reinvented herself as a main-tour doubles specialist, officially coming out of retirement in 2013 -- the same year she was inducted into the International Tennis Hall of Fame. She would then win her first Grand Slam title since 2006 at the 2015 Australian Open, taking the mixed-doubles event with Leander Paes.

The titles began to pile up soon thereafter. She and Sania Mirza won three majors together, before partnering with Chan to run through the draw in New York.

Who knows, maybe there will be more to come. As Hingis wrote in her retirement declaration: "This isn't a good-bye. As history shows, I haven't been able to stay away from tennis for very long in the past."

I'm not sure she meant that literally, but given her history, maybe we should read it that way.