Bastia - Britain's Chris Froome says he is confident cycling has moved on completely and is no longer ravaged by doping, as the 2013 Tour de France got underway on Saturday.
In an interview with France 2 television, the Kenyan-born Team Sky rider, who is the favourite to win the 100th edition of the sport's most famous race, hit back at comments attributed to the disgraced Lance Armstrong on Friday.
Armstrong told French daily Le Monde on Friday that it was "impossible" to win the Tour without doping during the period when he dominated the sport between 1999 and 2005.
Froome, whose Team Sky colleague Bradley Wiggins won last year's Tour, said he believed cycling was now clean but acknowledged that it will take a long time for it to emerge completely from the shadow of doping.
"It may not have been clean in the times of Armstrong, but things have changed one hundred percent now," he said.
"I am sure that when Bradley won the Tour last year, we did so without doping of any sorts.
"I understand that questions will be asked of me if I win, but that is the responsibility that I have to accept."
Froome may be this year's favourite, but his Tour did not get off to the best of starts.
France 2 reported that the 28-year-old fell from his bike and appeared to suffer a knock to the knee as the peloton paraded through Porto-Vecchio at the start of the opening stage.
He was then forced to change bike for the 213-kilometre ride up Corsica's east coast to Bastia.