If Chris Froome is fed up of having his credibility questioned again following his stunning win on Mont Ventoux, he can take some comfort from the words of his biggest rival on Monday. Alberto Contador saw his Tour de France chances suffer another crushing blow when he ceded 1min 40sec to Froome on Sunday\'s 15th stage to fall 4min 25sec behind the British rider in the overall standings. Froome\'s stunning performances have been greeted with scepticism by some members of the public and media as memories of the Lance Armstrong scandal remain fresh in the minds of everyone. However, Contador for one believes that it is wrong to question the man who seems a certainty to win the 100th edition of the sport\'s greatest race. \"There is no reason to doubt about Froome,\" insisted the Spaniard at his rest-day press conference in Avignon in southern France. \"He is a professional rider who has been performing at a really high level all year, and I think that his results are the fruits of the work he puts in and nothing else. \"I fully believe that he is clean. That is why the doping controls are there, isn\'t it?\" Contador knows only too well about doping controversies having served a two-year ban after testing positive for clenbuterol on the 2010 Tour de France. He was also stripped of that year\'s Tour title, leaving him with just two yellow jersey wins, to his name in 2007 and 2009, and remained edgy when it came to questions on the subject on Monday, even threatening to leave the press conference. He insists his focus is on recovering for one last assault on Froome, even if he admits that he cannot realistically compete with the Team Sky man at the moment. \"We came here to win but the leader is a level above everyone else. Face to face, at the moment he cannot be beaten,\" he said. \"It is true that the last week will be very demanding and tactically there will be more opportunities open to me.\" After Tuesday\'s 16th stage to Gap and Wednesday\'s individual time-trial, there will be three days in the high Alps, with climbs of L\'Alpe d\'Huez, the Col de la Madeleine, and Annecy Semnoz all on the menu. From: AFP