Lance Armstrong fired a parting shot at the doubters who dogged his career after bowing out of cycling with a seventh successive Tour de France win.
The American has faced numerous allegations of drug abuse since recovering from cancer and dominating the sport since his first win in 1999.
"To the cynics and the sceptics, I'm sorry you cannot believe in miracles," Armstrong said on the podium in Paris.
"This is a hard sporting event and hard work wins it. Vive le Tour forever."
Armstrong is the most tested athlete in the world but has never been found guilty of doping.
And he has 11 pending legal actions against those he believes have libelled him over the years.
"I won it once, twice, three, four, five, six, and seven times, so of course they ask those questions," added Armstrong.
"When you don't answer as they like, they make up the answer for you.
"Now I need a period of quiet and peace and privacy. I've had an unbelievable career. There's no reason to continue. I don't need more."
Armstrong has plenty to keep him busy in retirement, including the Lance Armstrong Foundation, whose yellow wristbands have raised $51m (£29.3m) for cancer sufferers.
In addition, the 33-year-old Texan is co-owner of the Discovery Channel team and manager Johan Bruyneel is anxious to utilise Armstrong's vast experience and knowledge.
Armstrong has also spoken of running for governor of Texas, while he also has three children and a rock-star girlfriend [Sheryl Crow] to consider.
Armstrong has a high profile in America where he has raised interest of cycling to unprecedented levels.
The Outdoor Life Network, the only channel in the States that broadcasts live coverage of the Tour, said ratings were 40% higher this year than in 2004.
The number of registered road racers has risen to 31,300 from 28,300 in 1999.
And America now has a number of top-class road racers, including Levi Leipheimer, who finished sixth overall in this year's Tour, and Floyd Landis, who finished ninth.
Indeed, Armstrong's retirement will leave a huge void in the sport in general.
"He contributed to the myth of the Tour," said Christian Prudhomme, the deputy race director.
"Next year the suspense will be far higher, there will no longer be a huge favourite. The boss who ruled the Tour de France will be gone."
Armstrong's departure offers hope to Jan Ullrich, the 1997 champion from Germany who has finished runner-up five times - three times to Armstrong.
He finished third this time, but will be 32 next year and knows it could be his last chance to win another title.
Italian rider Ivan Basso, who finished third in 2004 and second this year, is another potential champion, as is Kazakhstan's Alexandre Vinokourov who won Sunday's final stage.
Armstrong himself has singled out Spain's Alejandro Valverde as the possible "future of cycling".
Bruyneel, meanwhile, said it would be impossible to replace Armstrong in the Discovery team.
"I start from the idea that we can't replace him," said the Belgian.
"We have a few guys in the team who can step up and take responsibilities in the team, but it's a lot to ask for.
"Or we could go out and look for someone who can try and replace Lance - but that's not easy either."