Days after stunning the sports world by announcing she had failed a drug test at the Australian Open in January, Maria Sharapova thanked her fans for their "wonderful words" that put a smile on her face.

The Russian faces a ban of up to four years pending an investigation by the International Tennis Federation after testing positive for meldonium, which some researchers have linked to increased athletic performance and endurance.

"I woke up yesterday morning with an inbox, in full capacity of love and compassion," five-times grand slam champion Sharapova, 28, posted on Facebook. "In this moment, I am so proud to call you my fans.

"Within hours of my announcement, you showed me support and loyalty, which I could only expect to hear when someone would be at the top of their profession. I wanted to let you know that your wonderful words put a smile on my face.

"I'd like to play again and hope to have the chance to do so. Your messages give me great encouragement. This message isn't anything else but to say thank you. Thank you very much."

Sharapova, who has struggled with multiple injuries in recent years but is known for her never-say-die approach to the game, said she was prepared to battle through her latest setback.

"New day, new start," the former world number one wrote on Facebook. "It is fair to say that this day was not average.

"Nothing came to mind at 6am, except that I am determined to play tennis again and I hope I will have the chance to do so. I wish I didn't have to go through this, but I do - and I will.

"I needed to sweat, to push through and grind as I have done most of my life, so I made my way to the gym. That's when I realized a bunch of tinted windowed cars were following me. The good old paparazzi, back on the trail."

Sharapova, the world's highest-earning sportswoman, has accepted full responsibility for her mistake in taking a drug that has been outlawed since Jan. 1, having previously used it on the advice of her family doctor for a decade.

The International Tennis Federation's anti-doping programme calls for a four-year suspension for a positive test. That ban can be reduced in various circumstances, such as if the player shows no significant fault or negligence.