The Associated Press

SAINT-DIZIER, France - Now Lance Armstrong gets serious. His bid for a fifth straight Tour de France title begins in earnest today in team time trials. By day's end, Armstrong hopes to be wearing the leader's yellow jersey.

That would put him in excellent position before cycling's showcase race heads into the arduous climbs up the Alps on Saturday.

Armstrong conserved his strength Tuesday and finished 69th in the third stage, won by Italy's Alessandro Petacchi.

Armstrong is 12th overall, 19 seconds behind leader France's Jean-Patrick Nazon.

Today, squads race separately against the clock over a 43-mile course. Each rider gets his team's time, meaning Armstrong's challengers - or Armstrong himself - could lose seconds or minutes if their squads perform badly.

Today "is really the first decisive move of the race," said Dan Osipow, general manager of Armstrong's U.S. Postal Service team.

"With a bad team time trial, you can lose a handful of minutes, and where do you find those minutes again when the Alps come?" he said. "We want to gain time on all of our rivals."

Armstrong's squad races last because it leads the overall standings among the Tour's 22 teams. That will allow the riders to see how Armstrong's rivals did.

The route from Joinville to Saint-Dizier starts with a significant climb. Officials from Armstrong's team scouted the route.

"The beginning's hard," Armstrong said. Last year, U.S. Postal placed second, 16 seconds behind the Once team.

"We all want the yellow jersey," team spokesman Jogi Muller said. "It's within reach; we've got an incredibly strong team."

Armstrong is trying to match the record of Spain's Miguel Indurain, who won five straight Tours from 1991-95.

He has played it safe so far, trying to avoid accidents that pose a constant risk in the first week.

On Tuesday, Petacchi sped to the finish in a sprint marked by another crash. It was his second stage win in three days.

At a glance

Third stage: Charleville-Mezieres to Saint-Dizier, a 104-mile ride toward eastern France.

Winner: Italy's Alessandro Petacchi, in 3 hours, 27 minutes, 39 seconds.

How others fared: Four-time

champion Lance Armstrong finished in 69th place. 1997 Tour winner Jan Ullrich crossed at 18th. Tyler Hamilton, riding with a fractured collarbone, placed 43rd.

Next stage: Joinville to Saint-Dizier, a 43-mile time trial in which teams set off in five-minute intervals.