Lance Armstrong has seized complete control of the Tour de France with an awesome display of power cycling to win the 15.5 km individual time trial.
The American, bidding for a record sixth overall Tour victory, blasted round the 21 hairpins on the twisting climb to the Alpine ski resort in 39 minutes 41.47 seconds to annihilate his nearest rival Ivan Basso on Wednesday
It was his third stage win on this year's Tour and came a day after he took over the yellow jersey with a stunning victory on the climb to Villard-de-Lans.
"There was a lot of emotion and adrenaline, this mountain is special for me and for the Tour," he said, before criticising the behaviour of some of the tens of thousands of fans lining the route.
"There were lots of fans, and it was a little scary. To me, sincerely, it was not a good idea to have a time trial at l'Alpe d'Huez. It's over now but a lot of German fans were just disgusting. C'est la vie...
"The crowds are always close on the climbs but I was lucky to get through today."
Italian Basso, one minute 25 seconds down at the start of the 16th stage and Armstrong's one serious rival, could only finish eighth, 2:23 behind, after being overtaken by Armstrong on the lung-busting climb.
"I was a little surprised. A spectator told me I was a minute ahead and I could not believe it," Armstrong added.
Basso retained his second place but is now 3:48 adrift and will need the American to crash or suffer an extraordinary collapse if he is to win the Tour.
Jan Ullrich, so often Armstrong's main challenger in recent years, was also impressive on the classic climb which attracted tens of thousands of fans to the high-altitude resort.
The grimacing German, the 1997 Tour champion, was second, a massive 61 seconds slower than the greatest rider of his generation. Ullrich is now fourth overall and in danger of missing the podium for the first time in his seven Tours.
His T-Mobile team mate and compatriot Andreas Kloeden was third, 1:41 behind, and now looks a serious threat to Basso for the second step on the podium on Sunday.
Kloeden will start Thursday's final 204.5 km mountain stage to Le Grand Bornand 5:03 behind Armstrong who is the first rider to win in l'Alpe d'Huez with the yellow jersey on his back.
He is also the sixth rider to win twice at the top of one of the Tour's most famous climbs, having also won it in 2001.
But he narrowly failed to beat the late Marco Pantani's record for the climb proper -- the stage started 1.5 km before the foot of the hill -- clocking 37:36 to the Italian's 37:35.
The only slight worry for Armstrong came before the start of the stage when it was found that his bike, which had been designed especially for the time trial, was too light by 180 grams.
His mechanics worked hard to fix the problem and he was finally allowed to use the bike by race stewards.