Italian Rinaldo Nocentini took over the Tour de France leader's yellow jersey as Spaniard Alberto Contador dramatically replaced Astana teammate Lance Armstrong in second place overall on Friday.
On the first of three consecutive days in the Pyrenees mountains Frenchman Brice Feillu upset the form book to claim an impressive victory after 224km of racing from Barcelona.
However, it was Contador's attack of a small group containing all the main favourites inside the final two kilometres of the 10.1km climb to Arcalis which provided the most drama.
The Spaniard's effort moved him up from third to second place overall at only six seconds behind Nocentini, and well within sight of the race lead.
Astana team manager Johan Bruyneel said their principal strategy had been to allow an early breakaway to go all the way to the finish.
But he played down suggestions that Contador's attack was designed to rubber stamp his status as the team's official leader.
"No one had specific instructions to attack," said Bruyneel, who added that he would have been happier if Nocentini had more of an advantage on Contador. "Six seconds is not a lot. We'd hoped for a bit more. Our second strategy was just to set the tempo and wait for the attacks. I thought a rider like (Carlos) Sastre, (Cadel) Evans or (Andy) Schleck might attack.
"But I think the wind was a factor," he added. "In the end it was good for us because it allowed us to keep the team more or less together."
Feillu, racing at the Tour for the first time and the brother of Agritubel teammate Romain, attacked a small group of frontrunners 5.8km from the finish of the 10.1km climb to the race's first summit finish.
A second peloton including all the yellow jersey contenders at that point trailed the frontrunners by around five minutes.
After a first attack from two-time Tour de France runner-up Cadel Evans, Armstrong and Contador's Astana team took things in hand.
Evans' brief acceleration was easily countered by Armstrong, and after an attempt by the Australian's teammate Jurgen Van den Broeck, Contador flew away from the group and went on to finish the race on his own.
It was initially announced that the Spaniard, the 2007 champion, had done enough to take over the yellow jersey after he came over the finish 3:26 behind Feillu and ahead of Armstrong's group.
AG2R-La Mondiale (ALM)'s Rinaldo Nocentini (C) rides with teammate Christophe Riblon of France and French cycling team Agritubel's Brice Feillu over his shoulder en route to taking the yellow jersey from Fabian Cancellara Friday in Andorra
That honour, however, went to Nocentini, who rides for the French AG2R team.
"I knew I had a chance of taking the yellow jersey today," said Nocentini, racing at his first Tour after years of asking his AG2R manager.
Overnight leader Fabian Cancellara of the Saxo Bank team dropped down the overall standings after struggling to keep pace with the chasing peloton.
Feillu showed his ambition by jumping into an early breakaway that worked together to build a lead of over 13 minutes on the peloton.
Because it contained no real yellow jersey favourites - Nocentini started the day 3:13 behind Cancellara - they were allowed to race ahead.
Brice Feillu's reward on the day? The climber's polka dot jersey
At the end, a well-timed acceleration allowed him to distance his breakaway rivals and soon he was racing on his own towards the biggest win of his career.
"I can't believe it! It's my first Tour and now I've won a stage. In fact, it's my first victory of the year," said the 23-year-old Feillu.
© AFP 2009
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