Cycling: Armstrong left trailing by Contador

Seven-times winner cannot respond to attack on final climb by team-mate and favourite

(BAS CZERWINSKI / AP )

All it took was one searing late attack on the race's first mountain-top finish in Andorra, and Spain's Alberto Contador has finally demonstrated why he is the favourite in this year's Tour de France.

Although still not wearing the yellow jersey – that shifted, in one of the Tour's quirkier developments, onto the unlikely shoulders of Rinaldo Nocentini – Contador is now just six seconds behind and poised to pounce.

Equally importantly, Contador's move brought no reaction from his Astana team-mate Lance Armstrong, who slid from second to third overall, eight seconds back from Nocentini.

Speculation had been rife that after showing such strong form in the largely flat first week, Armstrong might attempt to rein in Contador when the Tour hit the Pyrenees, and he said afterwards that the Spaniard's move "had not formed part of the day's original plan''.

But the seven-times Tour winner either would not or could not respond to the Spaniard's charge off the front, and he lost 23sec to Contador by the summit of Ordino-Arcalis.

Contador made his move with just three kilometres left to go on a stage that had started at sea level in Barcelona, and then risen relentlessly for hour after hour through Cataluniaa's wild interior to the 2,300 metre high Andorran peak.

It was too late for Contador to go for the stage win, which went to the most tenacious rider of a day-long break of nine, Frenchman Brice Feillu. Yet the ease with which the 2007 winner bounded away from the other favourites strongly suggests that the Spaniard is, as Armstrong says, "the best climber in the world''.

"He's realised that he had to take the race by the scruff of the neck if he wants to win it,"said the Astana manager, Johan Bruyneel.

Part of the same breakaway as stage-winner Feillu, Nocentini recognised his chances of staying in yellow over the next two days in the Pyrenees were limited. "I'm the first person to be surprised to be here talking to you journalists," the Italian, in his first Tour, said afterwards.

If Nocentini provided one of the biggest surprises, Britain's Bradley Wiggins' excellent 12th place on the stage has confirmed that after three Olympic gold medals on the track, the Londoner is now fast progressing as a climber. Always close to the front of the Armstrong group, the Garmin-Slipstream rider remains in fifth place overall, 46sec down on Nocentini – by far his strongest ever performance in the Tour.

"I've been saying all along that physically I had it in me to do something here," Wiggins said. "I proved in the prologue I'd got my climbing legs and apart form that one day [stage three] when we were all caught with our pants down, I've ridden a perfect race. I felt great, and I'll help [team leader] Christian [Vande Velde] all I can in the mountains, but I don't want to get too excited about it. This race is three weeks long, and if you go too deep early on, you can pay a high price later on.''