PEYRAGUDES, France -- Frenchman Alexandre Geniez won a grueling 15th stage of the Spanish Vuelta that ended with a summit finish in his home country Sunday, while Vincenzo Nibali fended off his rivals' attacks to retain the overall lead.
Geniez broke away on a solo escape before the last of four category-one climbs to claim the 140-mile stage that started in the principality of Andorra, passed through Spanish territory, and finished at the Peyragudes summit.
The 25-year-old Geniez, riding for FDJ.FR, crossed the finish line in 6 hours, 20 minutes, 12 seconds. Michele Scarponi was second, more than three minutes behind, and Nicolas Roche was third before the group of favorites finished together with Nibali in front.
"I wasn't able to enjoy it until the last two kilometers," Geniez said after the biggest victory of his career. "You never know if you are empty and it could mean the end. It has been my best day."
Nibali, the Giro d'Italia winner, showed his good form by staying with Alejandro Valverde, Joaquim Rodriguez, and Christopher Horner each time they tried to pull away.
Nibali kept his 50-second lead over Horner. Valverde is 1:42 behind the Italian, with Rodriguez trailing by 2:57.
"It was a tough day. It was very cold and windy," Nibali said. "Besides, Purito (Rodriguez) and Horner tried to attack. I tried to attack as well, but with the wind blowing against me I couldn't pick up the pace. I felt strong but I preferred to save my energy for what's to come."
The Vuelta is proving as demanding as was expected when organizers announced that 13 of its 21 stages would be held in the mountains.
Rain and cold forced 16 riders to retire -- with some showing signs of hypothermia -- during Saturday's uphill ride into Andorra. Another 10 riders, including world road race champion Philippe Gilbert and world time trial champion Tony Martin, couldn't continue during Sunday's stage that saw varying temperatures, showers and patches of fog.
That leaves only two of the 22 teams -- Nibali's Astana and Euskaltel-Euskadi -- with all of their riders.
Valverde said that he had taken extra clothing along after the cold had almost caused him to crash on Saturday.
"I felt well (today), but I looked at my rivals and saw they weren't doing too bad either," said Valverde, who won the Vuelta in 2009. "It's difficult. They are very strong. But I have good sensations and there's still a lot of racing to go."
Monday's 16th stage is the third and last in the Pyrenees, a 91-mile ride from Graus to Aramon Formigal. The three-week grand tour ends in Madrid on Sept. 15.