US Anti-Doping Agency chief executive Travis Tygart on Thursday called Lance Armstrong's admission of doping "a small step in the right direction," for the shamed cyclist.

"Tonight, Lance Armstrong finally acknowledged that his cycling career was built on a powerful combination of doping and deceit," said Tygart, who guided the USADA probe that led to Armstrong being stripped of the record seven Tour de France titles and banned from the sport.

Armstrong had previously dubbed USADA's investigation a "witch-hunt" and accused Tygart and his colleagues of pursuing a "vendetta" against him and going so far as to file a lawsuit questioning their jurisdiction.