Lance Armstrong and his Belgian team manager Johan Bruyneel cannot agree how many times the Texan looked over the 20-mile climb to this ski resort in the run-up to the Tour. "I always say five or six, Johan says three or four," said Armstrong yesterday.

These were the only figures over which there was any doubt: by finishing a clear minute ahead of Jan Ullrich, Armstrong took his second stage win in two days and the Tour is now his to win or lose.

It remains, however, to be won. Two mountain victories in two days mean that Armstrong will fly south-west to the Pyrenees today with a clear enough margin over Ullrich and Joseba Beloki - three minutes 34 seconds and 3.10 respectively - but the yellow jersey remains the property of the grizzled little Frenchman, Francois Simon, who finished precisely seven minutes behind Armstrong yesterday.

He is a popular maillot jaune, who still boasts more than 13 minutes lead over the American, but it was over 30 minutes on Sunday and the signs in the Alps which proclaimed "Simon in yellow in Paris" are Gallic fantasy.

The yellow jersey fits no more comfortably on his compact frame than the wobbly nostril expander strip he sported yesterday, and he is unlikely even to approach the eight days in yellow his elder brother Pascal managed in 1983.

Pain, however, is something the Simons know all about. Pascal spent six days in agony in yellow with a fractured shoulder, and yesterday Francois' sufferings, if not on that level, were painful to watch: his head dropped on one side, his mouth stiffening in a tic of pain.

If tomorrow's uphill finish at Plateau de Bonascre does not blow him away, then on Saturday in one of the five passes en route to one of the classic Pyrenean finishes at Pla d'Adet he will surely founder.

Founded in 1865, this little ski resort in the Belledonne Massif is no stranger to sporting legend in the making. It was here that Jean-Claude Killy took three gold medals - downhill, special slalom and giant slalom - in the 1968 winter Olympics, and the Col du Luitel, of which this climb is a part, was the setting for the legendary climber Charly Gaul's epic stage win in the 1958 Tour.

Gaul and Armstrong can now be mentioned in the same sentence: the speed with which Armstrong turns his legs as he goes uphill has been compared to the legendary "angel of the mountains", and this double of Alpine victories is simply exceptional. No one has won back-to-back Tour stages in the Alps since the Russian Piotr Ugroumov, ironically another protege of the infamous doctor Michele Ferrari, in 1994, and the last defending Tour winner to do such a thing was Eddy Merckx.

If he goes on to take that third Tour, Armstrong will owe much to the fact that he leaves nothing to chance. As well as the disputed number of reconnaissances up here, he also chose the Tour of Switzerland as a final warm-up specifically because it included a mountain time trial, not seen in the Tour de France since 1996.

The practice paid off in spades. He chose the perfect line on each hair-pin bend, and led at every checkpoint apart from the first, where he and Ullrich were level. He was sufficiently confident to back off slightly in the second part of the climb, allowing Ullrich to come back at him slightly, before piling the pressure on again in the final few kilometres to the little cluster of chalets and apartment blocks above the dense pine trees of the Premol forest.

The only threat to his progress came from over-zealous fans, who persistently ran the gauntlet by jumping out in front to yell encouragement, leaping back at the very last moment. To complete the perfect day, his family, wife Kristin and son Luke, arrived yesterday, and last night he and Kristin were due to open an envelope which contains a piece of paper from their doctor telling them the gender of the twins she is expecting this winter.

As at l'Alpe d'Huez the previous day, Ullrich and Armstrong presented a contrast in styles. The German clearly relies on strength rather than what the French call souplesse - the ability to turn the pedals swiftly and economically, which is Armstrong's forte. For the also-rans, style was academic in this horrendous combination of the Tour's two toughest disciplines: they finished the final one-in-eight ramp to the line with heads swaying, mouths gasping for air. Armstrong, however, was in a class of his own.