Alberto Contador realizes he is running out of time, and stages, to close the gap on his Tour de France rivals.

The Spaniard's bid for a fourth Tour title has yet to get going as the race enters its final week, a combination of bad luck and a nagging knee injury conspiring to make it difficult for him to launch his trademark attacks in the mountains.

"This is probably the hardest Tour I've done. I have lost a lot of strength since the beginning," Contador said on Monday - the 2nd rest day of the 2011 Tour de France. "It's true that without the time loss from the first stage I would be in a good position to win the Tour de France, and (just) waiting for the last time trial."

Contador must first find a way to claw back from a four-minute deficit on race leader Thomas Voeckler. He also lost time to Andy and Frank Schleck of Team Leopard-Trek and Luxembourg and two-time runner-up Team BMC Racing's Cadel Evans of Australia.

After 15 of 21 stages, seventh-place Contador trails Frank Schleck by 02:11, Evans by 01:54, Andy Schleck by 01:45 and Team Liquigas-Cannondale's Ivan Basso by 44 seconds.

Contador and his Saxo Bank-SunGard team have no choice but to be aggressive in the high climbs of the Alps this week.

The 17th stage Wednesday from Gap to Pinerolo features just one category 1 ascent and won't be as testing as the excruciating climbs Thursday and Friday that will leave riders exhausted before the 26-mile individual time trial on Saturday.

Stages 18 and 19 feature enormous treks up Col du Galibier, Col d'Izoard and L'Alpe d'Huez -- all of them known as HC climbs, or Hors Categorie, because they are too demanding to have a classification.

"The climbs in the Alps are different than the Pyrenees, they are longer and at a higher altitude," the 28-year-old Contador said. "Some riders will suffer from that. But we need to attack, that's for sure."

Contador lost a lot of time to the Schlecks and Evans when he was caught behind a pileup on the first stage.

The bad luck he had then set the tone for the rest of his race. It proved to be a bad omen with Contador falling on stages 5 and 9, banging his right knee twice.

"Without the time loss from the first stage I would be in a good position to win the Tour de France, waiting for the last time trial (to come)" Contador said through a translator.

After his spill on stage 9, Contador knew had to focus on damage limitation in the three grueling mountain stages in the Pyrenees.

Considering he was riding with an injury last week, Contador did remarkably well not to lose more than 33 seconds to Frank Schleck, 15 to Andy Schleck and 13 to Evans.

"I think everybody knows he is a champion. He is still a young rider but a young rider with a lot of experience," Team Saxo Bank-SunGard owner and manager Bjarne Riis commented and added "I think he knows how to handle situations when there are problems. Of course, you get frustrated when you're not at 100 percent, everybody gets frustrated. But, in another way, you know that you have to stay calm."

The unpredictable nature of this year's race still gives Contador some advantages.

It's seems uncertain which Schleck brother is the leader and which is the support rider, while Voeckler's unexpected presence means there is an extra cyclist to chase down. Then there is Evans and Basso, the Tour runner-up in 2005, to deal with.

If Contador recovers in time for the big Alps, he could rise up when the others are taking each other down.

"Each day that passes without knowing which card the Schleck brothers will play is more complicated," Contador stated and continued "In my opinion, they have to think about their attacks and to know which one is the best. The other one has to sacrifice himself, otherwise it will be very hard to distance riders as good as Evans and the others."

Riis turned the pressure up on the Leopard-Trek team by claiming he knows what tactics the Schlecks will use in the Alps.

"I know the Schlecks. I have an idea what's going on, but this is an idea we discuss between us," Riis commented and concluded "I believe that what we will see a spectacular race in the Alps."