ANGOULEME - Spaniard Alberto Contador was poised to win the Tour de France after holding off his rivals for the overall lead in Saturday's time trial won by his Discovery Channel team mate Levi Leipheimer.

Discovery Channel team rider Alberto Contador of Spain celebrates on the podium as he keeps the overall leader's yellow jersey after the 19th time trial stage of the 94th Tour de France cycling race between Cognac and Angouleme July 28, 2007. [Reuters]

American Leipheimer clocked the best time of one hour, two minutes and 44 seconds in the 55.5-km time trial, the 19th and penultimate stage, from Cognac at an average speed of 53.082 kph.

Australian Cadel Evans of the Predictor Lotto team was second ahead of Russian Vladimir Karpets of Caisse d'Epargne. The 24-year-old Contador came fifth.

Evans retained second place 23 seconds behind Contador in the overall standings, eight seconds ahead of Leipheimer.

The stage winner said: "I'm very happy for Alberto. When he crossed the line I was as happy as if it had been me, honestly."

"I've done all I could," said Evans.

"I lost 55 seconds in the ascent of the Col de Peyresourde, that is where I lost the Tour," the Australian said of one of the climbs in the Pyrenees in Wednesday's 16th stage.

Leipheimer said he would not try to leapfrog Evans in Sunday's final-stage parade from Marcoussis to Paris.

"If it was for the win it would be heartbreaking. But we've won this Tour and have two stage wins. I'm not going to attack Cadel tomorrow. He's a better sprinter anyway," the American said. 

Contador, who received the visit on Saturday of seven-times Tour winner and former Discovery Channel rider Lance Armstrong, is set to become the first Spaniard to win the world's greatest race since Miguel Indurain's fifth victory in 1995.

Leipheimer said of Armstrong's visit: "He's normally very calm and collected but today he was nervous.

"It brought back memories. He was taking care of little details, he was helping, asking if we needed anything. He was very much into the groove of what we were doing."

Contador is also about to become the first mere climber to prevail on the roads of France since Italian Marco Pantani in 1998.

He benefited from Michael Rasmussen's dismissal by his Rabobank team on Thursday for lying about his training whereabouts. The Dane held the leader's yellow jersey at the time.

Pre-race favourite Alexander Vinokourov was also sent packing after testing positive for blood doping following his victory in the Albi time trial last weekend.