AURILLAC, France, July 11, 2008 (AFP) - Spain's Luis Leon Sanchez stepped out of the shadow of Caisse d'Epargne team-mate Alejandro Valverde to win a dramatic 7th stage of the Tour de France here on Friday.

Luxembourg's Kim Kirchen, of Team Columbia, survived an audacious attempt to loosen his grip on the yellow jersey by a determined CSC team to retain the race lead with a six-second cushion on Australian Cadel Evans.

A tumultuous stage, held over 159km of hilly terrain in the Massif Central, saw a number of crashes and retirements, including that of former French champion Christophe Moreau.

Agritubel team leader Moreau, who was fourth overall in the 2001 edition, is the biggest name to drop out of the race so far, abandoning shortly after he dropped off the back of a chasing peloton.

Italian Damiano Cunego crashed around the 60km mark, the Lampre rider getting back on his bike but spending a tough day in the saddle following the CSC team's decision to subsequently up the tempo.

Sanchez had attacked several times throughout the hilly, second day in the medium mountains and got his just rewards following a final acceleration 4km from the finish line.

He left three of his former breakaway compantions in his wake, and won six seconds ahead of Schumacher and a 21-man bunch which included all the race favourites.

Sanchez pointed to the sky as he crossed the line to claim his first ever win in the world's biggest race.

He later explained it was to dedicate his win to his dead brother.

"I want to dedicate this victory to my brother who died in a motorbike accident three years ago," said Sanchez.

"We were really close, we rode together until the age of 21 and with my other brother, who plays football, we were always dedicating our victories to each other."

Sanchez, however, insisted that from now on he is likely to stick to Caisse d'Epargne's gameplan of getting their team leader Valverde, or 2006 winner Oscar Pereiro, back into the yellow jersey.

"We're here to help Alejandro or Oscar win yellow in Paris, and that's how we approach every stage of this race," added the 24-year-old Sanchez.

"Today I won mostly because of the circumstances of the race."

A disciplined start to the second day in the medium mountains eventually gave way to a thrilling day of tactical racing once Scotland's David Millar was eventually reeled in by the chasing bunch.

The peloton seemed in no mood to allow escapes to go early on but Millar, of the Garmin team, attacked one kilometre from the summit of the category four climb at Villedieu and eventually found himself with company.

A four-man break formed but because Millar began the stage in fifth overall at just 47secs behind Kirchen, he was never going to be given much rein.

"I decided last night that I was going to have one last try of trying to pull on the yellow jersey after I looked at the stage profile," Millar told AFP after finishing the stage 33secs behind Sanchez, which pushed him down to seventh place overall at 1:14 behind Kirchen.

A 24sec lead on the chasing bunch was quickly reduced after several teams joined Kirchen and his Columbia team in upping the pace.

The quartet were caught minutes later, and a solo attack by Sanchez soon gave way to a mass acceleration by the CSC team of yellow jersey hopeful Carlos Sastre.

CSC's decision came shortly after Cunego's crash at the 60km mark, but it appeared more designed to tire out Kirchen's Columbia team than leave the diminutive Italian climber behind.

It is a badly-hidden secret on the Tour that CSC's Schleck brothers Andy and Frank are no friends of their yellow jersey-wearing compatriot Kirchen.

After the race, CSC team manager Bjarne Riis refused to feed that theory.

"We have our own tactic like everybody else," he said.

"I can't speak for the other teams but we do what suits us best. Today's stage was very difficult, there was a lot of wind when we accelerated so for me it was the right time."

CSC's tactics left many riders trying to catch up as the main peloton split into pieces.

Around 25 leaders - including all the yellow jersey favourites - were then left in front, only to be joined by a larger group with 70km and three of the day's most difficult climbs to race.

Sanchez then launched his second big attack of the day on the lower slopes of the Col d'Entremont, prompting fellow Spaniard Josep Jufre Pou of Saunier Duval to follow.

The pair were joined by David de la Fuente and Vincenzo Nibali of Liquigas and they went over the summit of the category two Pas de Peyrol with a lead of 1min 30sec on the peloton.

The descent, however, proved far trickier. De la Fuente's downhill skills were exposed as he was forced to brake on the humid roads on several occasions while approaching tight corners.

He finally caught up with the leading trio and with 20km to the finish they held a lead of one minute on the peloton but in the end Sanchez was the only one capable of holding on.