Five-time Grand Slam champion Maria Sharapova is "saying goodbye" to tennis at the age of 32.
In an article written for Vogue and Vanity Fair, Sharapova said her body "had become a distraction" after a struggle with shoulder injuries.
The Russian won her first Grand Slam at Wimbledon in 2004 aged 17 and completed the career slam - all four major titles - by winning the French Open in 2012.
In 2016, she served a 15-month ban after testing positive for meldonium.
After returning from her ban in 2017, Sharapova struggled to recapture her best form and suffered from a number of injuries.
She has dropped to 373 in the world, her lowest ranking since August 2002, and has lost in the first round of her past three Grand Slam tournaments.
In announcing her retirement, she said: "I'm new to this, so please forgive me. Tennis - I'm saying goodbye.
"Looking back now, I realize that tennis has been my mountain. My path has been filled with valleys and detours, but the views from its peak were incredible.
"After 28 years and five Grand Slam titles, though, I'm ready to scale another mountain - to compete on a different type of terrain.
"That relentless chase for victories, though? That won't ever diminish. No matter what lies ahead, I will apply the same focus, the same work ethic, and all of the lessons I've learned along the way.
"In the meantime, there are a few simple things I'm really looking forward to: A sense of stillness with my family. Lingering over a morning cup of coffee. Unexpected weekend getaways. Workouts of my choice (hello, dance class!)"
Sharapova said her 6-1 6-1 first-round defeat by Serena Williams at last year's US open was the "final signal".
"Behind closed doors, 30 minutes before taking the court, I had a procedure to numb my shoulder to get through the match," she said,
"Shoulder injuries are nothing new for me - over time my tendons have frayed like a string. I've had multiple surgeries - once in 2008, another procedure last year - and spent countless months in physical therapy.
"Just stepping on to the court that day felt like a final victory, when of course it should have been merely the first step toward victory."
Sharapova did not play again in 2019 after that defeat at Flushing Meadows and has played just twice this year, including a straight sets loss to Croat Donna Vekic in the Australian Open first round.
BDST: 2046 HRS, FEB 26, 2020