ADELAIDE, Australia — Lance Armstrong lies 39 seconds off the overall lead after four stages of the Tour Down Under but is ready to defy pain and fatigue in his comeback race to chase victory in its remaining two stages.

Armstrong, 37, finished among the main bunch on Friday and in the same time as fourth stage winner and overall leader Allan Davis of Australia, moving up on general classification to 38th place among 124 riders remaining in the race.

He battled heat, hills and strong winds for the fourth straight day in a race which marks his comeback from a three year retirement, and he was still in a position after the fourth day to chase a victory over the weekend.

"Body was tired today, legs were tired as well," Armstrong said.

"And for sure, they'll open up the race tomorrow.

"I may be crazy but I think I can be there. I know I won't be riding away."

Saturday's 92.5 mile stage from Snapper Point to Willunga includes two cruel climbs up the Willunga Hill and has been identified by experts as the stage most likely to decide the race.

The Tour concludes Sunday with a 56-mile circuit around the streets of central Adelaide, the South Australia state capital.

Armstrong expects the race to suit the Australian sprinters again Saturday but will do as much as his body will allow to put himself in the race.

"You've gotta be strong and again it depends on the wind tomorrow on Willunga. If it's anything like it was in training it will be hard for anybody to ride," he said.

"It's disappointing but still it's January not later July (or) so I have to keep reminding myself.

"This is still the first race back after a long time and I'd be kidding myself if I expected to show up and pound people. That's just not the way it's going to work."

Armstrong said conditions had made the race hard as a comeback event after a three-year break.

"The break, the heat, the hills, the wind and the fact it's a stage race and it's been aggressive," he said.

"It's been harder than I expected but everyone will share that."

Davis took the fourth stage in a bunched sprint to the finish at Angaston, in the heart of the Barossa Valley wine region. Australian Graeme Brown, who won the third stage on Thursday, was second and Jose Rojas of Spain was third.

Armstrong's former teammate George Hincapie finished 19th for US-based Team Columbia and was 12th in the overall standings, 30 seconds behind Davis.

Vladmir Efimkin of Russia, Andoni Lafuente of Spain and Australian Travis Meyer led the stage for most of the day while sprinters such as Davis and Brown lurked with Armstrong among the pack.

The leaders broke away on the long, winding hill which riders mounted as they snaked out of Adelaide, through a rugged gorge into the Torrens River Valley, then into the Barossa.

But for the fourth time in as many days the stage was decided in a tight finish in which the Australians, favored by racing in their own season, were too strong.