Race leader Lance Armstrong [Images] dealt his rivals a big blow in the first Pyrenees stage of this year's Tour de France [Images] but has always made it clear Sunday's 205.5-km effort between Lezat sur Leze and Pla d'Adet would be the hardest.

The six-times champion dismissed any fears his form was on the way down or that the heat could have affected his performances by finishing second behind Austrian Georg Totschnig in Ax-3 Domaines on Saturday.

But there will be five mountains on Sunday's menu, including four first category ones, and then the 'beyond category' climb up to the finish in Pla d'Adet for Armstrong's rivals to try and upset him.

With his lead of one minute 41 seconds over Dane Michael Rasmussen, Armstrong appears unlikely to suffer a setback on the Porte d'Aspet, Mente, Portillon, Peyresourde and Val Louron passes, all of which he knows like the back of his hand.

"They're the classic Pyrenees passes we ride almost very year and almost always in this order," he said.

As a result, it will be extremely difficult for his opponents to catch him off guard and there is every chance the Discovery Channel leader will be the one to attack -- probably on the climb to Pla d'Adet, where he won a stage in 2001.

Winner of five individual stages last year, the American has yet to record a victory in this Tour and he will certainly hope to set the record straight in arguably the toughest mountain stage.

The first climb of the day, the Portet d'Aspet, will bring back painful memories for the Texan, whose Motorola team mate Fabio Casartelli crashed and died on the descent 10 years ago.

Tributes will be paid to the former Olympic champion when the Tour caravan passes the plaque in his honour.