Maria Sharapova has not set a timetable for retirement and still has the desire to succeed on the big stage despite having struggled since her comeback from suspension.
The five-time grand slam champion was banned in March 2016 after testing positive for meldonium. She did not return to the court until April last year and has found form and fitness hard to come by.
Though Sharapova won the Tianjin Open in October, she has been dogged by injuries in 2018, winning only five matches across four events.
Her ambition has not been checked by her results and injury issues, though, with the 31-year-old Sharapova telling CNN: "I didn't put any expectations on myself coming back after the suspension.
"Because missing that period of time at this age and after going through different things in my life, whether it's injury or surgery, just being away from the sport, even though you are resting your body and even though I was resting things that were hurting before, you can never replicate what you do in a match environment.
"I am still working through that, and I am still getting that back, and that takes a while.
"In terms of where my mind is, my motivation and the desire that I have for what I continue now when I am on centre court, when I am away from the court and I have moments where my body feels like it's not where it should be, where I am not healthy, or where it is just a day where I feel like being somewhere else, I still get through it, and I find a way to get through it and to me, that's the best sign."
On the possibility of retirement, she added: "I haven't set a timetable for myself, but I've always said that I would do it on my own terms.
"And when I say 'on my own terms', so many questions are goal-oriented. You start a season and it's like what's your goal?
"When you've experienced grand slam victories, it's absolutely natural to have that goal in your mind.
"It would be silly for me to say my goal for this year is to win a lower-tier tournament because I strive to be on the big stage and to win on the big stage.
"I've experienced it, and I know what it's like and I want that feeling again. I continue to work for that."
Sharapova faces Caroline Garcia in the first round of the Stuttgart Open on Tuesday.