Spaniard Alberto Contador brushed off queries over his credibility as a clean, potential Tour de France winner after pulling on the race's yellow jersey on Thursday.
A day after Denmark's Michael Ramsussen exited the race in disgrace, Contador took over and has three days in which to defend his lead ahead of the final stage in Paris on Sunday.
However, with the race still reeling from two positive doping tests, two teams being thrown out, and the controversy of the Rasmussen affair, Contador was not given an easy ride after he finished with the bunch to maintain his 2min 23sec lead over Australian Cadel Evans.
It didn't help that last year the 24-year-old from Madrid was entangled in the Spanish doping affair dubbed 'Operation Puerto', which has cast a cloud over the sport since May 2006.
Contador was cleared by a Spanish judge of any involvement, and on Thursday promised he was 100 percent clean.
The Discovery Channel rider added that he did not have any links to shady sports doctors, who for the past decade have been employed by some of the world's top riders.
"If I wasn't clean, then I wouldn't be here. I've undergone all the required doping tests, both at the race and before it," said Contador, who could become the first Spaniard since Miguel Indurain to win the Tour.
"Operation Puerto was something which concerned my former team, and I was simply in the wrong place at the wrong time."
Rasmussen's forced withdrawal from the race followed his team's discovery that he had lied to them about his whereabouts in June.
For the past week the Dane, now sacked by Rabobank, had come under huge pressure following revelations that he had missed four random doping controls in the past 18 months.
Contador, who came into the race hoping to win the white jersey for the best placed rider aged 25 and under, said he had no opinion on Rasmussen.
He simply compared the Dane's disgraceful exit to the former race leader being involved in a crash.
"I was surprised when I heard the news (on Rasmussen)," added Contador, who beat Rasmussen in the tough climbing stage to Plateau de Beille, before the Dane took his revenge on Wednesday's 16th stage.
"But I was also happy because I had attacked a lot in the final kilometres on Wednesday.
"When a rider crashes you can pick up the yellow jersey, so I'm looking at the situation a bit like that."
Contador also denied any association with Italian sports doctor Michele Ferrari. Prior to being ejected from the race for returning a positive A sample for positive for homologous blood doping, pre-race favourite Alexandre Vinokourov said he had been working with Ferrari.
Ferrari's most famous client was seven-time Tour de France winner Lance Armstrong. But Contador, now with Armstrong's former team Discovery Channel, said he had nothing to hide.
"I don't even know what Doctor Ferrari looks like! I've never met him and I don't work with him. My doctors are the team doctors and I only work with them."