American Floyd Landis has denied cheating on the way to winning this year's Tour de France.
Landis' Phonak team has revealed that the 30-year-old tested positive for unusual levels of testosterone after winning stage 17 of this year's race.
Asked directly by American magazine Sports Illustrated if he had cheated, Landis replied: "No, c'mon man."
Landis said he "can't be hopeful" a back-up test would clear him, but hoped to prove the imbalance was natural.
"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," he said.
"All I'm asking for is that I be given a chance to prove that I'm innocent"
"But it was not from an exogenous outside source of testosterone.
"I wouldn't hold it against somebody if they don't believe me. I'm a realist," added Landis, who has been suspended by his team.
"All I'm asking for is that I be given a chance to prove that I'm innocent. Cycling has a traditional way of trying people in the court of public opinion before they get a chance to do anything else.
"I would like to be presumed innocent until proven guilty - since that's the way we do things in America."
He faces the prospect of being stripped of his Tour title and sacked by Phonak if his B sample confirms the positive test.
The result of that test is expected to be known by Monday.
Landis, who won the Tour by 57 seconds from Oscar Pereiro, said that he was innocent of injecting testosterone or using a testosterone patch.
"I think there's a good possibility I'll clear my name"
"I think there's a good possibility I'll clear my name," said Landis but he added: "Regardless of whether this happens or not, I don't know if this will ever go away."
Landis is due to have hip replacement surgery in the coming weeks and he says that injections of cortisone, a steroid used to treat pain, may have had an effect.
He also revealed that he has been suffering with a thyroid problem which has required hormone treatement.
"I've had a thyroid condition for the last year or so and have been taking small amounts of thyroid hormone," he said. "It's an oral dose, one a day."
Landis produced one of the most memorable rides in Tour history when he stormed to victory in stage 17 by almost six minutes.
The win put him back into contention for the yellow jersey, a day after his chances looked to have evaporated when he cracked on the final climb of stage 16.