LONDON (Reuters) - Rafa Nadal branded comments made by former French tennis player Yannick Noah about doping as "stupid" on Sunday, saying they were the words of a "kid". In an interview in French newspaper Le Monde, Noah said the best way to combat doping was to legalise the use of drugs and also appeared to accuse Spanish sport in particular of using "magic potions". Asked about Noah's comments at the ATP World Tour Finals where an ailing Nadal beat American Mardy Fish despite an upset stomach, the Spaniard was clearly angry. "What can I say? That's going to be difficult to explain what I feel in English," the 25-year-old 10-times grand slam champion told reporters. "What he said is completely stupid and he knows better than nobody. To say that today is a totally stupid thing because you know how many anti-doping controls we are having during all the season year by year.