ADELAIDE, Australia — Three years after retiring as a seven-time Tour de France champion, Lance Armstrong is ready to race.

The 37-year-old cancer survivor said he is "hungry and motivated" to launch an audacious comeback at the Tour Down Under on Tuesday.

Armstrong settled nerves agitated by the long layoff when he raced in a criterium warmup to the tour Sunday, finishing 64th among 133 riders. For the next six days he will test the wisdom of his comeback on the hills and in the heat of rural South Australia.

His expectations for his first professional tour since the 2005 Tour de France are "modest" — he insists he doesn't expect to win — but says his "competitive juices" will be flowing and high personal standards will shun failure.

"Failure would be a broken collarbone," he said. "If I were the first guy dropped on Tuesday that would be a failure. That would not be good.

"But I don't have any clear ambitions or standards in my mind. To me it's successful just being here and getting into racing earlier than I would have. I have a job to do and my job is to train hard and try to be the best bike rider I can be and take this (anticancer) message around the world — and it kicks off here."

Tuesday's first stage curls 80 miles from Norwood to Mawson Lakes, and includes climbs to a peak of over 1,300 feet, a relatively gentle welcome back to road racing for the Austin cycling great.

It may be Saturday's fifth stage, taking in the Willunga Hill, which proves whether he has the legs as well as the heart and passion to make his return more than a footnote to a great career.

"I still go in with modest expectations mixed with nerves, mixed with excitement," Armstrong said. "I'm not a slacker but with no major goals other than make it through and get back into the rhythm of racing.

"Those juices are flowing through me even in a local race in Austin (Texas). You're looking around, you're not sure if it's excitement or nervousness — we call them butterflies. That's healthy and if I didn't have that then I probably shouldn't be here."

Johan Bruyneel, Armstrong's close friend and the head of the Astana team, to whom he first confided his comeback decision in August, has worked hard to manage expectations for his lead rider. But Bruyneel also knows him too well to rule out a miracle.

"It is not our ambition or intention to win this race," Bruyneel said. "But if Lance feels good at a certain stage, he'll want to test himself. I think he's good enough to be in the front group. He's a competitor and if he wasn't serious about doing this he wouldn't be here.

"I think he can be in the top classification, but winning is something else."

Armstrong's mere presence has already cast a spell over many of his rivals, turning hardened competitors into star-struck boosters of the American rider.

Stuart O'Grady, one of Australia's strongest chances in the race, has no doubt Armstrong will make his presence felt.

"When someone of Lance's stature comes back to the peleton he's not going to just ride around," he said. "With someone of his record, confidence and ego, I can't see the rest of us dropping him on the Willunga Hill.

"Lance is a super freak athlete and we shouldn't forget that."

Armstrong laughs off those assessments.

"You tell them I've been drinking beer for 3½ years," Armstrong said. "I'll tell you this, if the opportunity is there I will definitely take it. I will take every opportunity to be at the front of the race and be active. ... No bluffing and no hiding."

Armstrong expects to be regularly drug tested during the race and has put in place his own testing regime, managed by American anti-doping scientist Don Catlin.

Stringent testing measures implemented by the Australian Sports Anti-Doping Agency involve blood and urine screening for substances such as EPO and human growth hormone. Any rider testing positive for an illegal substance faces an automatic four-year ban from cycling.