Stuttgart - Roger Federer had no sympathy for Maria Sharapova, saying on Thursday he backs a "zero tolerance" stance against doping.
Russian star Sharapova was handed a two-year doping ban on Wednesday after testing positive for the banned medication meldonium at January's Australian Open.
The 29-year-old admitted in March that she simply hadn't realised meldonium, which was added to the World Antio-Doping Agency's banned substance list in January, was no longer permitted -- she had been taking the medication for 10 years.
"I only heard the headlines, I didn't quite get into all the details but to me it's about zero tolerance," said Federer after his 6-4, 5-7, 6-4 victory over Taylor Fritz at the Stuttgart Open on Thursday.
"It doesn't matter if they did it on purpose or not -- I don't really see the difference. You need to know what goes into your body, you have to be 100% sure of what's going on, if you're not, you're gong to be damned.
"Of course she's got the right to fight the case, like everybody else as well. I'm just for zero tolerance.
"I stay by my word that we should be saving blood samples for 10, 15, 20 years to come, so you have to scare away the people who think they could cheat.
"You have to scare them so they will not do it, so they could retroactively also be banned, and take away titles and so forth."
Meanwhile, bottled water producer Evian became the latest sponsor to stand by Sharapova despite her ban.
Evian joined Nike and Head in choosing to maintain their partnership with the Russian, citing the International Tennis Federation's assertion that she had not doped intentionally.
"The ITF tribunal concluded that Maria Sharapova's contravention was not intentional. Following this announcement, Evian has decided to maintain its long-lasting relationship with the champion," said the French company in a statement.
Nike and Head released similar statements on Wednesday.
Nike said they hoped "to see Maria back on court" and would "continue to partner with her".
Head described the ITF ban as "based upon a flawed process" and accused WADA of breaking their own rules "in determining whether or not meldonium should be banned".
Sharapova has vowed to take her appeal to the Court of Arbitration for Sport.
"While the tribunal concluded correctly that I did not intentionally violate the anti-doping rules, I cannot accept an unfairly harsh two-year suspension," fumed Sharapova on Wednesday after hearing of the ITF's suspension.