Lance Armstrong, wearing the leader’s yellow jersey, and pop singer Sheryl Crow after the Discovery Channel team won the fourth stage team time trial on Tuesday. (Reuters)

Blois: Lance Armstrong seized the Tour de France yellow jersey in dramatic fashion on Tuesday when his Discovery Channel team sped to victory in the fourth stage ahead of the CSC outfit of previous leader David Zabriskie, who crashed near the finish.

Armstrong’s team set too fast a pace over the 67.5 km team time trial between Tours and Blois, clocking one hour, 10 minutes and 39 seconds at an astounding average speed of 57.31 kph, the fastest in a Tour.

Zabriskie, winner of Saturday’s opening individual time trial, crashed in the final two kilometres of the stage when his chain snapped and lost 1:28 on Armstrong.

His CSC teammates were just two seconds slower than Armstrong’s outfit on the line, meaning the 26-year-old American would probably have retained top spot had he not crashed.

Instead it was business as usual for six-time champion Armstrong. He holds a 55 seconds lead over team mate George Hincapie.

“It was more or less the plan. We first of all wanted to win the stage but to get the jersey on top is a bonus,” said Armstrong.

“It feels very good actually, for a few reasons ? it’s always good to win this event and show that the team is strong. It’s also the first yellow jersey for Discovery Channel.

“It’s nice to give them their first”, said the 33-year-old.

After only four days, Armstrong, riding the Tour for the last time, has a commanding lead. The first rider from another team in the overall standings is third-placed German Jens Voigt, of CSC, who lies 1:04 behind.

Germany’s Jan Ullrich’s, whose T-Mobile outfit was third in the stage, is 14th, 1:36 adrift of Armstrong while Kazakh team mate Alexander Vinokourov is 1:21 behind.

CSC’s leader Ivan Basso trails Armstrong by 1:26 in the same time as Zabriskie.

Armstrong is ideally placed in his quest for an unprecedented seventh Tour win and everything is, as usual, going to plan.

Zabriskie’s crash was unexpected but it might also have had something to do with the frantic pace set in the struggle between the Discovery Channel and CSC teams.

“It’s unfortunate. I wish I could comment more, but I could not really see what happened,” Armstrong said.

“The team time trial is so hard at the end that everybody is at the limit. When we came into the city, there were lot of turns, and it’s easy to make a mistake like that.

Regardless of Zabriskie’s misfortune, Armstrong’s performance was impressive as he played a leading part in his team’s effort.

Discovery Channel’s teamwork and a strong tailwind helped them ride the fastest tour stage ever.

The previous highest average speed had been set by Briton Chris Boardman in the 7.2-km prologue in 1994. The fastest team time trial was ridden at an average of 54.93 kph by Italian crew Gewiss Ballan in 1995. (Reuters)