Born in Russia, and "discovered" by Martina Navratilova at an exhibition event in Moscow, Sharapova moved to Florida as a child and trained at the Nick Bollettieri Tennis Academy.

"We'll miss her, baby. She's very special," Bollettieri told AP last year, when Sharapova returned to his academy as she worked her way back from her latest shoulder procedure. "The tour will miss her. ...Always competitive. All business."

Sharapova burst onto the tennis scene at 17 by upsetting Serena Williams to win Wimbledon in 2004. She would beat Williams again at that year's season-ending tour championship to improve to 2-1 against the American-and never won another one of their matchups, dropping the next 19 in a row.

Powerful at the baseline, and famous for a never-give-up attitude, Sharapova reached No 1 for the first time at 18 in 2005. After adding her second major trophy at the US Open the following year, she collected an Australian Open title in 2008, and then won the French Open in 2012 and 2014.

Sharapova is one of only six women in the professional era to win each major tennis title at least once. She made 10 Grand Slam finals in all, going 5-5; the last came in 2015 at the Australian Open, where she was the runner-up to Williams.

At the 2016 Australian Open, where Williams beat her in the last eight, Sharapova tested positive for newly banned drug meldonium.

After initially being given a two-year suspension, Sharapova appealed to the Court of Arbitration for Sport, which reduced the penalty, ruling she bore "less than significant fault" in the case and could not "be considered to be an intentional doper".