Portugal's Manuel Cardoso won the exhausting third stage of the Tour Down Under on Thursday as Germany's Andre Greipel held his overall lead in the first event on this year's UCI ProTour calendar.

The Footon rider summoned up all his remaining energy to win the 132.5-km stage in the South Australia mountains held in oppressive temperatures topping 40 degrees Celcius.

"I dont think I have a chance to win overall despite my win here, I have had a lot of hard days over the first couple of days of this race, I am probably too far behind," said Cardoso.

"But it was really important for me, it is my first pro race, first pro team - so it is a very important win."

Spain's Alejandro Valverde (Team Caisse d'Epargne) finished second while Australia's road race world champion Cadel Evans was third.

"It was a bit of a strange old day, a bit harder than most expected, pretty windy and the heat of course," Evans said.

"Coming into the last kilometer it was like riding in slow motion almost, everyone was so exhausted."

Andre Greipel (Team HTC-Columbia), who won the first two stages, finished with the front group to hold on to the leader's jersey with three days to go.

Team RadioShack's Lance Armstrong needed a new rear wheel after puncturing a tyre. He recovered to finish in the main peloton in 23rd place but said he was too tired to even join in the sprint finish.

"I can't go, I'm dead," he said.