LAGOS DE COVADONGA Spain (Reuters) - Poland's Przemyslaw Niemiec won the 15th stage of the Tour of Spain as Alberto Contador moved further ahead of Britain's Chris Froome at the end of a grueling final ascent on Sunday.
Spaniard Contador, who retained the overall leader's red jersey, battled against the negative tactics of Alejandro Valverde, second overall, and Joaquim Rodriguez to finish a few seconds behind his two compatriots.
The Tinkoff-Saxo rider attacked time and again in the final climb - a 12.2-km ascent at an average gradient of 7.2 per cent to Lagos De Covadonga.
But Rodriguez and Valverde refused to cooperate to get rid of Froome, who was struggling a few meters behind.
The Briton limited the damage and still lies third overall, 1:20 behind Contador after losing seven seconds to the Spaniard at the end of Sunday's 152.2-km ride.
"At the end of the day he actually lost time to Valverde and Rodriguez but he gained time on Froome," said Tinkoff-Saxo sports director Tristan Hoffman.
"It was a difficult situation tactically but I think he managed the situation very well. Tomorrow, there's another big day in the mountains and we'll do everything we can to maintain the lead."
Frenchman Warren Barguil was the first to shake off a small group of favorites in the final climb but it was Contador who went hard in the final six kilometers.
Froome, who was yo-yoing at the back, appeared to crack several times but always managed to fight his way back, never losing sight of Contador.
The double Tour de France champion, looking to win the Vuelta for the third time, was outsprinted by Valverde and Rodriguez in the finale as the Movistar and Katusha riders snatched six and four seconds of time bonuses respectively.
Niemiec, of the Lampre-Merida team, was the sole survivor of the day's breakaway and held off the trio of rivals to win the stage, crossing the line five seconds ahead of Valverde and Rodriguez.
Monday's 16th stage is classed as the queen stage, a 160.5-km trek to La Farrapona, featuring four categorized climbs.
Writing by Julien Pretot; Editing by Steve Tongue and Justin Palmer