Maria Sharapova who was banned for two years on doping charges on Wednesday received no sympathy from fellow tennis superstar Roger Federer, who said he backs a "zero tolerance" stance against doping. "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 going to be damned," Roger said.