Tour de France winner Floyd Landis denied on Thursday (July 27) taking performance-enhancing drugs during the race and said he would fight to clear his name after testing positive for the male sex hormone testosterone. "I don't know what the explanation for it is, whether it was a mistake or whether it's an occurrence from some other circumstances that go on in the race or something I did...But it was not from an exogenous outside source of testosterone," he told reporters in a teleconference call. When asked by reporters if he had taken any banned substances to boost his performance during the race, Landis replied: "No". If Landis's B sample confirms the result, the 30-year-old U.S. rider is certain to be stripped of his victory, becoming the first Tour winner to be disqualified for doping. Spain's Oscar Pereiro, who finished second in the overall standings, would be declared the winner if Landis is disqualified. Landis said on Thursday: "...most of the public has an idea about cycling because of the way things have gone on in the past...a lot of people are going to assume I'm guilty before I have the chance to defend myself... "Unfortunately, I don't think it's ever going to go away no matter what happens next," said Landis, who was speaking from Europe, but would not be specific about his exact location. "...all I'm asking for, just from me is that I be given a chance to prove that I',m innocent." Landis said he was determined to clear himself of the doping charges, but was resigned to the fact that the stigma of the positive test might never leave him. "Cycling has a traditional way of trying people in the court of public opinion before they ever get a chance to do anything else," he said. Landis provided the positive sample after a brilliant ride in the 17th stage, a gruelling ride to Morzine in the French Alps, a day after a disastrous showing had appeared to ruin his chances of victory. When asked to explain his incredible ride in the crucial 17th stage, Landis replied: "There's 20 stages in the Tour and everyday you see a fabulous performance. Explain the other 19."