Andy Schleck snatched his second stage win of the Tour de France on the last mountain leg of the race on Thursday as leader Alberto Contador took a big step towards clinching a third overall victory.
The defending champion from Spain retained his eight-second advantage over 2009 runner-up Schleck with the race now likely to be settled in Saturday's 19th stage -- a 52-km individual time trial between Bordeaux and Pauillac.
Contador is normally a far better time trialist than Schleck.
The pair were peerless in the last ascent to the Pyrenees summit first climbed in 1910 and embraced after crossing the finish line in the same time at the end of Thursday's 174-km 17th stage from Pau.
Spain's Joaquim Rodriguez took third place, 1:18 behind.
Schleck, winner of the eighth stage in Morzine-Avoriaz, produced his anticipated attack on Contador 10-km from the summit and the Astana team leader was soon the only rider capable of overtaking him.
Rodriguez, Russia's Denis Menchov, Spain's Samuel Sanchez, Belgian Jurgen Van den Broeck and Dutchman Robert Gesink were in a second group trying to limit the damage.
Schleck tried to increase the pace and change tempo to upset the 2007 and 2009 champion but soon discovered there was no dropping the Spaniard on a cold and foggy day on the Pyrenees.
Friday's 18th stage takes the peloton from Salies de Bearn to Bordeaux over 198-km.