And despite her lengthy absence, the Russian Federation appears to have returned in strong form.
In her second match after a 15-month doping ban, Sharapova hit nine aces and held serve throughout. Sharapova hasn't dropped a set in three matches this week.
Wednesday's match was the Russian's first since losing to Serena Williams in the quarterfinals of the 2016 Australian Open, and her first match on clay in almost two years. Her disqualification came to an end of April 26, and the organizers of the Premier series tournament in Stuttgart issued a special invitation known as the wild card to her.
"I don't think that's right", she told Turkish broadcaster TRT World.
"She's a cheater, and so to me - I mean, I don't think a cheater in any sport should be allowed to play that sport again".
Maria Sharapova is through to the semi-finals of the Porsche Grand Prix in Stuttgart after a 6-3 6-4 win over Anett Kontaveit. Sharapova has also been granted wildcards into the Madrid and Rome WTA tournaments, but must wait until May 16 to learn if she will get a wild card for the French Open.
Her ultimate goal is to gain entry into the French Open, as she can earn a place in the qualifying draw for Roland Garros only if she reaches the final in Germany.
The three-time champion continued her impressive comeback from a 15-month-long drug ban on Thursday when she decimated compatriot Ekaterina Makarova in straight sets 7-5, 6-1 to enter the quarter-final. The drug was added to the banned list of doping drugs because it increases the amount of oxygen in the blood that flows to the heart, which experts believe causes improved performance.
"I thought I moved a lot better today, and was more comfortable with the ground and the surface", Sharapova said.
"I'm way above that".
"I was studying, I was working, I was working on my business, I formed friendships that I did never have the time for to form", she said.
Makarova cleverly mixed up the height and depth of her shots during rallies on the very quick Stuttgart clay with Sharapova still lacking match practice.
The Russian says she is just relishing her return after so long on the sidelines. The only thing I can control is what I do out there, and those are my words.