Former world number one Sharapova, who was banned after testing positive for meldonium, made a winning return to competitive action yesterday when she defeated Roberta Vinci 7-5 6-3 in the first round of the Stuttgart Open.

But Bouchard believes that should never have been allowed to happen.

Asked whether Sharapova was still an idol of hers and what her feelings were on the Russian being handed a wild card for Stuttgart, the 23-year-old Canadian told TRT World: "I don't think that's right.

"She's a cheater and so to me, I don't think a cheater in any sport should be allowed to play that sport again.

"It's so unfair to all the other players who do it the right way and are true.

"I think from the WTA it sends the wrong message to young kids: cheat and we'll welcome you back with open arms. I don't think that's right and (she is) definitely not someone I can say I look up to any more."

Sharapova was back on court just 24 hours after completing her suspension for failing a drugs test.

The 30-year-old tested positive for meldonium at the 2016 Australian Open and her original two-year ban was reduced on appeal.

Sharapova admitted taking the cardiac drug at a press conference last March, insisting her only mistake was not realising the substance had been added to the banned list at the start of 2016.

As she had her ranking suspended until her ban expired, the five-time grand slam winner has had to rely on a wild card to compete in Stuttgart.

The Madrid and Italian Opens have followed suit with wild cards, and the decision to give her automatic entry to events she would otherwise not qualify for by ranking has drawn the ire of several prominent professionals, including Andy Murray, Caroline Wozniacki, Agnieszka Radwanska and Italy's Vinci.