By Julien Pretot
MUR DE BRETAGNE, France (Reuters) - Alexis Vuillermoz earned France its first victory on this year's Tour de France, his final kick proving too hot to handle for the big guns in the eighth stage on Saturday.
The AG2r-La Mondiale rider attacked twice in the final climb, a brutal two-km ascent at an average gradient of 6.9 percent, and countered overall leader Chris Froome less than one-km from the line.
The 27-year-old Vuillermoz beat Ireland's Dan Martin (Cannondale-Garmin) by five seconds as Spain's Alejandro Valverde (Movistar) led the top names 10 seconds behind to take third place after a 181.5-km ride from Rennes.
"I really wanted to go for the stage win today, it was all or nothing," Vuillermoz, a former mountain biker, told reporters.
Froome still leads Slovakian Peter Sagan (Tinkoff-Saxo) by 11 seconds and American Tejay van Garderen (BMC Racing) by 13.
"That was a tough climb, but my team mates did a great job in bringing me to the front, I was in the best position," said Froome, who once he realized Vuillermoz was gone focused on controlling his rivals.
Defending champion Vincenzo Nibali of Astana lost 10 seconds to the other members of the Big Four (Froome, Spain's Alberto Contador and Colombian Nairo Quintana).
Contador is seventh 36 seconds behind Team Sky's Froome, Nibali is 13th 1:48 off the pace with Quintana in 16th place, 1:56 adrift.
Inside the final km, Froome upped the pace in typical fashion, glued to his saddle with his head bent, but Vuillermoz hit back, suggesting he could be tough to handle in the mountains.
Vuillermoz, who took 11th place overall in the Giro d'Italia in 2014 in his second year as a professional, is supposed to ride in support of team mates Jean-Christophe Peraud and Romain Bardet, second and sixth overall in last year's Tour.
Sunday's ninth stage is a 28-km team time trial before the first rest day of the three-week race, which then heads to the mountains.
"In the Pyrenees the race for the yellow jersey will really start," said Froome.
German Andre Greipel (Lotto-Soudal) lost the green jersey for the points classification to Sagan, who was fourth on the day.
(Reporting by Julien Pretot; Editing by Ken Ferris)