The Associated Press

LYON, France - Lance Armstrong finished 39th in the sixth stage of the Tour de France on Friday, retaining second place overall behind U.S. Postal Service teammate Victor Hugo Pena.

Armstrong, trying for a record-tying fifth straight Tour win, chose to conserve energy for the mountain stages that begin today. His team's goal is to help Armstrong match the record held by Spain's Miguel Indurain, said Pena.

"Tomorrow the Tour is really going to start; we're going into the Alps," Pena said. "I'm going to do my job as a teammate to make sure Lance wins his fifth Tour de France."

Today's 140.12-mile stage from Lyon to of Morzine-Avoriaz is the first of three days of alpine ascents. Four others come later in the Pyrenees.

Alessandro Petacchi won Friday's stage to claim his fourth victory in six legs. Petacchi, an Italian who rides for Fassa Bortolo, finished the 142.6-mile run from Nevers to Lyon in 5 hours, 8 minutes and 35 seconds as temperatures reached 90 degrees.

In the final yards, Petacchi surged past Australian Baden Cooke of FDJeux.com and Italian Fabrizio Guidi of Team Bianchi.

Today, Petacchi will wear the green jersey awarded to the fastest sprinter. He said that if he gets over the Alps, he hopes to retain the jersey all the way to the finish in Paris on July 27.

"I know it's something very special what I'm doing here," said Petacchi, who also won sprint finishes in the first, third and fifth stages.

Friday's climb up the 2,336-foot Cote des Echarmeaux, 44 miles from the finish in Lyon, was barely a bump compared to some of the ascents ahead, including the 8,728-foot Col du Galibier ahead Sunday.

Petacchi said he was tired throughout the stage, but his teammates helped shield him from the wind, enabling him to stay with the pack for a sprint finish.

At a glance

Stage: Nevers to Lyon, a 142.6-mile route.

Winner: Italy's Alessandro Petacchi, in 5:08.35 for his fourth stage victory of this Tour.

How others fared: Four-time winner Lance Armstrong finished 39th. American Tyler Hamilton, riding with a fractured collarbone, finished 48th.

Next stage: Lyon to Morzine-Avoriaz, 140.12 miles in the French Alps.