The Spanish cyclist finished Thursday's second stage in 13th place to trail overall leader Philippe Gilbert of Belgium by 15 seconds. Contador finished the 116-mile stage in the same time as winner John Degenkolb of Team HTC-HighRoad.

"I'm not in the same shape like in other years but you can never discount victory," said Contador, who was racing for new Team Saxo Bank-SunGard. "It hasn't been too bad since these haven't been very tough stages. I'm very happy because the team is also working very well. Tomorrow will be the day to draw conclusions."

Contador tested non-negative for clenbuterol in last year's Tour de France but had a proposed one-year ban overturned after showing the banned substance came from contaminated meat.

While he was cleared to race, Contador could still have all results wiped out should an appeal rule against him. The International Cycling Union and the World Anti-Doping Agency can still appeal to the Court of Arbitration for Sport.

For now, the three-time Tour de France champion expects Friday's 111-mile stage to be decisive in his quest to win a third straight title in Portugal.

"Tomorrow will be a tough day with a mountain finish that will do me good, but the legs are not what they have been in other years," Contador said. "I'll try my best as I'm motivated to do well for my team and for all those people who supported me over these past months.

"We'll see what happens," he said.