Lance Armstrong insists it is still too early to talk about a record sixth Tour de France victory despite leading the race by more than four minutes.
When asked if he thought he would go on to win the Tour, Armstrong said: "I don't know, I really don't know. Let's wait a couple more days."
But rival Jan Ullrich conceded the Texan was now a certainty for the win.
The German, who currently lies fourth, said: "Lance is in a different class at the moment. He can't be caught."
Armstrong has been in imperious form throughout the Tour, winning four stages, including Thursday's victory on stage 17.
Armstrong led home Andreas Kloden, Ullrich, Ivan Basso and Floyd Landis, in a stunning sprint for the line.
"This year I feel amazing on the bike - I have recovered well after every stage," said Armstrong.
"My condition is super and like everybody saw, the team was unbelievable today, they controlled everything. I had no problems.
"Today was a tactical race, everyone was trying to win the stage, and I thought I would try my chances as well."
Ullrich revealed afterwards he had been bidding to put T-Mobile team-mate Kloden in position for the stage win.
He told the team's official website: "We had arranged things between us about five km from the line: I would mark (Armstrong's team mate) Floyd Landis and Andi
would try to ward off Lance. It was perfectly set up.
"When Klodi attacked like a bat out of hell, opening up a gap of 60, 70 metres back to us, then I thought to myself 'he has it in the bag'.
"At the end of a stage that nobody deserved to lose, only one fact remains: Lance is too strong."
This year's race finishes in Paris on Sunday.