Nocenti in yellow as Contador climbs

France's Brice Feillu won stage seven, a 224km hike from Barcelona to Andorra, but it is what went on just behind the gutsy Agritubel rider that will grab the headlines as Contador asserted his authority as Astana team leader ahead of team-mate Lance Armstrong, the record seven-time Tour winner.

AG2R La Mondiale's Nocentini, part of a nine-man breakaway group which included Feillu and led the field almost all stage, finished fourth and far enough clear of the big guns at the top of the general classification to take the maillot jaune.

The Italian started the day in 32nd position in the overall standings but ended it six seconds clear of second-placed Contador, who broke away from a stretched-out peloton in a punishing stage-ending, hors-categorie climb up to Arcalis to finish ninth.

The Spaniard's late show of strength pulled him clear of Armstrong, who came home 22 seconds later.

Armstrong, firmly put in his place by Contador on Friday, will head into stage eight on Saturday third in the standings, two seconds behind Contador.

Fabian Cancellara lost his grip on the yellow jersey after being dropped by the peloton 5.5km from the end, midway through the final climb. He plummets down the standings after finishing more than eight-and-a-half minutes behind the leaders.

Feillu, a winner in six hours 11 minutes and 31 seconds, was followed home by second-placed Christophe Kern (Cofidis) and Milram's Johannes Frohlinger, who was third.

But the little-known Nocentini - riding in his first Tour - stole the limelight. He is the first Italian in nine years to lead the Tour.

"I am very happy," he told France 2. "I came here to win a stage but I finish today with the maillot jaune."