Tour de France champion Alberto Contador lost time on the leaders and suffered a painful knock to his leg when he crashed towards the end of the first stage of the 2010 Paris-Nice.

The race favourite crashed three km from the finish in Contres after being dropped from the front following a harsh effort by the Caisse d'Epargne team of last year's winner Luis Leon Sanchez.

"I picked up a pretty good knock. The pain is quite sharp. I am quite worried," Spaniard Contador told reporters.

"I was on the left side on the road and there was a wave in the peloton. I fell in the grass with Heinrich Haussler.

"It was quite a hard fall but as I was still over three km from the finish I had little choice but to come back into the bunch."

"It's not the time lost I'm worried about but how I will feel in the morning," Contador said.

American Levi Leipheimer was another of the big names to lose time in the treacherous stage. Held back by one of several pile-ups in the peloton, the RadioShack team leader lies seventh overall, 25 seconds behind race leader Lars Boom.